Download Grade 12 Physics ISU independent study unit new book Word

Grade 12 Physics Independent Study
Nelson 12 Textbook
Instructions:
 Every Grade 12 physics student is responsible for learning several topics on his/her own, much
like university. This independent study gives the student an opportunity to learn how to learn
on their own. The main reference textbook is Nelson12 Physics, however, there are other high
school reference books at school or public libraries that can be of help.
 Do the suggested reading in the following pages along with the questions and problems
indicated.
 As you read and do the questions, make notes and summaries on definitions, concepts and
formulas. Answer non-numerical questions as well. Put these in one notebook. In another
notebook, write out solutions for the problems assigned in GUFSA format.
 At the end of November and early December, the teacher will interview with each student on
their progress. At this time, students must show the teacher their notebooks and work to date.
The notebooks are not marked, but it is strongly advised that students make two good notebooks
to do well on the culminating exam.
 Students must also set up an eight inch by eleven inch aid sheet on both sides that summarize all
the key formulas, concepts and definitions studied. This aid sheet can be used on a culminating
exam worth 10% of the final mark in the course. The culminating exam will occur roughly on
the third week of January with a fixed date determined in late December.
 If students are having difficulties with any of the ISU work, they are welcome to come in and
get extra help with the teacher at lunch or after school.
 The ISU material will not be covered on the final exam. The final exam just covers material
learned in class during teacher presentations.
Page #1
Electric Fields:
1. Read p320 to321 What subatomic particles are the basic units of charge? What is the law of electric charges?
What does +e and -e stand for? P320 If an object has equal numbers of protons and electrons, what is its total
charge? If an object has too many or an excess of electrons to balance the #protons, what type is its charge? If an
object has too few or a deficit of electrons to balance the #protons, what type is its charge? What is law of
conservation of charge? P321 What is the SI unit of electrical charge? What is the charge on the electron and
proton in terms of Coulombs? Do you think an object can have a net charge of -3/4e ? Why or why not? Why does
the alpha particle or Helium nucleus have a charge of 3.20 X 10 -19 C? P321
2. Read from middle of p321-326. Define: conductor, insulator Contrast placing charge on an insulator compared to
placing a charge on a conductor like a metal. Briefly explain how to charge an object a) by friction b) by contact
c) by induced charge separation d) by induction via grounding Do Q1,Q5 p326 check ans p719
3. Read p327 to p332 Define: electric force What is Coulomb's Law? Memorize it. What is the equation for
Coulomb's law? Memorize it. What does each symbol in Coulomb's equation stand for? What is Coulomb's
constant in the SI system? Note well: Coulomb's equation only gives us the magnitude of the electric force, so
don't substitute negative signs for charge into the formula. Even though force is a vector, Coulomb's formula is a
scalar equation. After the calculation, use the law of charges to figure out the direction of the electric force. If
there are two or more other charges, find the individual magnitudes of the electric forces, find the direction of the
electric forces as prescribed, then use vector addition rules to find the net force acting. What principle is this? See
p329 How is Coulomb's law similar and different from Newton's law of universal gravitation? See p328 Review
tutorial #1, sample problem #1,#2, #3 p330-332 Solve Q1 to Q3 p332 Check answers same page Solve Q1 to Q10
p333 Check answers p719 p373 Q55-Q57 Q59-Q65
4. Read p334 to344 An electric field can be loosely described as a region of space where an electric force is exerted
on charges. Briefly describe how electric fields create images on LCD displays. P334 Fill in the blanks: The
more precise definition of the electric field is electric force per unit _________________ charge with an SI unit of
_______. see p334 There are two equations for electric field, one is a vector equation and one is a scalar equation
that can be used to determine the magnitude of the electric field due to a point charge. Memorize these formulas
and be able to derive the scalar equation. Be sure you know what the symbols stand for. See pages 334 - 335 Note
again well: the scalar equation only gives us the magnitude of the electric field due to a point charge, so don't
substitute negative signs for charge into the formula. Even though electric field is a vector, this is a scalar
equation. After the calculation, figure out the direction of the electric force on a positive test charge at this point in
space using the law of charges depending on whether the nearby point charge is negative or positive. If there are
two or more other point charges, find the individual magnitudes of the electric fields on a positive test charge,
determine the direction as prescribed, then use vector addition rules to find the net electric field acting. Review
tutorial #1, sample problems #1 and #2 then try Q1-Q3 p337 check answers same page
5. Read p338-341The electric field at any point in space near a point charge can be represented by electric field lines.
Fill in the blanks: The direction of electric field lines tells us the direction of the electric force on a ____________
test charge. The __________________ of the field lines is proportional to the magnitude of the electric field. A
positive point charge transmits an electric field directed radially ___________________. A negative point charge
transmits an electric field directed radially _______________________. The magnitude of the electric field is
inversely proportional to the ________________ of the distance from the charge. Define electric dipole. Sketch the
electric field lines near a) a positive point charge b) a negative point charge c) an electric dipole d) two identical
charges near each other. Can you explain these electric field line patterns? The book fails to mention how the
direction of the electric field can be determined from a curved electric field line pattern. By drawing a tangent line
to the curved electric field line at a point in space, we can determine the direction of the electric field and therefore
the direction of the electric force on a positive test charge placed at that point. Read over p341 What set up can
create a uniform or constant electric field? Sketch and briefly describe the electric field line pattern between and
near the edges of this set up. What is the electric field magnitude outside of this oppositely charged parallel plate
set up? What does the constant electric field between parallel plates depend on?
6. Read over p342 – p344 What is the purpose of an electrostatic precipitator? Use a diagram to describe how it
works. Compare the magnitude of the earth's electric field on a clear day with the minimum magnitude of the
electric field emitted by the prey of the electric field-detecting hammerhead shark.
7. Solve Q1,2,3,4,6,7 p345 check answers p719 P373 Q67, Q68, Q69, Q 70 , Q71, Q72, Q73 check answers p719
8. Read p346 -p347 BUT there are a few errors and clarifications. The title on the bottom of p346 should read “Work
and Electric Potential Energy” . Define and know electric potential energy. This section deals with a constant nonzero electric field, like between oppositely charged parallel plates. If we place a charge at rest in that electric field,
page #2
the electric field is able to do work on that charge. We say the electric field has electric potential energy. As work
is done on the charge, the electric field's potential energy decreases i.e W = -ΔEE or ΔEE = -W The book is dealing
with displacements parallel to the electric force or electric field, so the book uses a short cut equation for work,
W = FE Δd
so ΔEE = -W = - FE Δd = -q E Δd Memorize this, but you should know that electric potential
energy is a scalar even though we substitute for vectors in this equation. Also realize the vectors involved are
collinear and therefore we can represent them as integers. For instance, if an electron is placed at rest in an
electric field, the electron will move in the opposite direction of the electric field or the electric force, (remember
the electric field points in the direction of the electric force on a positive test charge) positive work is done and
there is an electric potential energy loss. So when you substitute into the equation ΔEE = -q E Δd , if the electric
field is in a positive direction, the displacement must be negative, and in this case we must substitute the sign of the
charge which is negative. Overall a negative X negative X negative yields a negative, or a loss in electric potential
energy. Remember signs are important in vector equations. In general and in the absence of applied or frictional
forces, if the electric potential energy decreases the kinetic energy increases and vice-versa so that mechanical
energy is conserved. In equation form ΔEk = -ΔEE or mv22/2 - mv12/2 = +q E Δd . Memorize and know this.
Use these equations to review and redo tutorial #1and the sample problems, then do Q1,Q2, Q3 p349 Ans on pg
9. Read p350 to p353
10. Define and know: electric potential definition in words, electric potential defining equation and SI unit, equivalent
electric potential units in terms of Joules and Newtons. If we double the charge in a constant or uniform electric
field, how does the electric potential energy and electric potential change? Define and know: electric potential
difference definition in words, electric potential difference defining equation and SI unit. In a uniform or constant
electric field such as between a parallel plate apparatus, derive the equation ΔV = - E Δd . Keep in mind the book
did not emphasize that E and Δd are vectors. Know it. If there is no change in electric potential for a very small
change in displacement, what is the electric field strength over that displacement? Fill in the blanks: positive
charges move naturally from _______________potential to___________________ potential. Electrons move
naturally from __________________ potential to ______________________ potential. In a uniform electric field
without friction or applied forces, keep in mind ΔEk = -ΔEE or mv22/2 - mv12/2 = +q E Δd as before, but
ΔV = - E Δd so mv22/2 - mv12/2 = - q ΔV Memorize this. Review and redo sample problems #1 and #2 on p352
and 353. Do practice p353 Q1,2,3 Check answers on the same page. Do Q1 to Q10 on p354. Check answers p719
11. Read p355 to p361
12. What is the defining equation for the electric potential due to a point charge? Memorize. At an infinite distance
from a point charge, what is the value of the electric potential? What is the defining equation for the electric
potential energy due to two charges near each other. Memorize. When two charges are separated by an infinite
distance, what is the value of the electric potential? Learn how to calculate electric potential and electric potential
energies due to point charges by reviewing and redoing sample problems p357 to p360, then do q1 to q4 on p360
check answers on same page. Do questions 1, 4 to 7 p361 check answers p719
13. Read p362 to p365
14. What is the main conclusion from Millikan's oil drop experiment? What is meant by elementary charge and
fundamental physical constants? What is the charge in Coulombs for the electron and proton? Can we have a
charge equal to 1/4 of an elementary charge? Derive Millikan's equation q = mgd/ΔV. What do the symbols in
q = Ne stand for? How does the equation help us? Learn how to use these equations in Millikan problems by
reviewing and redoing sample problems p363-p364 then do Q1 to Q3 p364 Check answers same page then do Q1
to Q7 p365 check answers p719
15. Do p373 Q74 to 76, Q78, Q80 to Q90 Check answers p719
Now try these review problems:
1. What is the electrical force between charges of 50.0 nC and 100.0 nC if they are 5.00 cm apart? (Ans 0.0182 N
repulsive)
2. Two charges exert an electrical force of “K” Newtons on each other. If one charge is doubled, the other charge is
divided by three, and the distance is multiplied by four, what is the magnitude of the new electrical force? (ANS
(1/24) K N)
3. Two identical positive charges of magnitude +2.0 C are 16 cm apart. A third charge of +3.0 C is on the right
bisector of the first two charges with the angles 36.9° as shown. Find the size of the net electrical force on the 3.0
C charge? ( Ans 6.5 X 1012 N)
3.0 C
2.0 C
36.9°
36.9°
16.0 cm
2.0 C
page #3
The electric field strength is 4.0 N/C [E]. What is the electrical force on a charge of -5.0 C charge in this field?
(Ans 20 N [W])
5. A -6.0 C charge experiences a 30.0 N [W] electrical force. What is the electric field strength? ( Ans 5.0 N/C [E])
6. A +2.0 C charge is 20 cm to the right of a -3.0 c charge. What is the electric field on the line exactly halfway
between the two charges? (Ans 4.5 X 1012 N/C [Left] )
7. Millikan's experiment determined that all charge is an integral multiple of the elementary charge. What is the value
of the elementary charge? If a neutral atom gains 3 electrons, what is its charge? (Ans 1.6 X 10-19C, 4.8 X 10-19 C
)
8. It takes 4.2 X 10-3 J of energy to move a 1.2 X 10-6 C of charge against an electric field from one point to another.
What is the magnitude of the potential difference between the two points? ( Ans 3500 J/C or 3500 V)
9. Parallel plates are 5.0 mm apart and have a potential difference of 300 Volts between them. If a +2.0 C charge is
between the plates, what is the magnitude of the electrical force on the charge? ( Ans 1.2 X 105 N)
10. In a Millikan-type experiment, two horizontal parallel plates are 2.5 cm apart. An oil drop of mass 1.5 X 10 -15 kg
remains at rest when the potential difference between the plates is 460 V with the upper plate positive. How many
excess or deficit electrons does the drop have? (Ans 5 excess electrons)
11. An alpha particle of +2 elementary charges and mass 6.7 X 10 -27 kg can be given some speed by placing it at rest
on the positive side of a 2000 Volt parallel plate apparatus. Ignoring any gravitational effects, what speed does the
particle have when it reaches the negative plate? (Ans 4.4 x 105 m/s)
4.
Magnetic Fields:
1. Read p376 What does MRI stand for? What do MRI devices use to make very strong magnetic fields around the
human body? What is the medical use of the MRI?
Read p378 – p382 In your own words, summarize how the northern lights (aurora borealis) and southern lights
(aurora australis) occur? Note that B is the symbol for magnetic field and is a vector, but magnetic field is not the
same as magnetic force Fmag Fill in the blanks: Iron filings around a bar magnet show the __________
_____________. Similar to the law of charges and electrical force, like poles ____________ each other and unlike
poles ________________ each other. Unlike electric fields that can result from single charges, magnetic fields will
always result from a magnetic _____________. Unlike charges and electrical forces, you can never have only a
_____________ pole or only a _______________ pole. Magnetic field lines move _______________ from the
north pole and _______________ toward the south pole. See p379 Draw magnetic field lines around a a bar
magnet. How does the shape of the magnetic field around a magnetic dipole compare with the shape of the electric
field around a charge dipole? See Fig 3 p379 Fill in the blanks: Magnetic field lines always form __________
loops. Inside a magnet, the field lines go from the ____________pole to the ____________ pole. Top p380 Sketch
the magnetic field lines inside and outside a horseshoe magnet. Look back to Fig 3 p379. Note the direction of the
magnetic field B is along the tangent line to the curved magnetic field lines. This direction is the same direction
that the north pole of a compass needle points. The density or number of field lines increases near the poles. Note
also that magnetic field lines, like electric field lines, never cross. Fill in the blanks: The earth's core acts like a
giant ______________ magnet. The earth's north geographic pole is actually a __________ magnetic pole,
however, it is conventional to call it otherwise. Last few sentences p380 What happens to the polarity and position
of the earth's magnetic poles over time? P381 top A magnetic field produces a magnetic force on a moving
charged particle that is ________________________ to both the direction of the magnetic field and the particle's
velocity. Top p382 Use this fact to explain how cosmic rays, fast moving charged particles from the sun and stars,
get deflected at the equator by the earth's magnetic field but spiral around magnetic field lines near the magnetic
poles of the earth. Explain why a magnetic field can never speed up a moving charged particle. P381-382
2. Read p382 – p385 State Oersted's 1820 “principle of electromagnetism” and know it. The direction of current
used in this course an in this textbook is called “conventional current”, which is the flow of positive charge from
the positive terminal to the negative terminal. Compare conventional current with tha actual flow of electrons in a
circuit. See sidebar p382 Sketch the magnetic field around a straight wire conducting current. State and
memorize the right-hand rule for a straight conductor. P382 Sketch the magnetic field of a looped wire carrying
current. Indicate the direction of conventional current in your diagram. P383 Define and know what a solenoid is.
Sketch the magnetic field inside and outside of a solenoid carrying current. State and memorize the right-hand rule
for a solenoid. Fill in the blanks: Applying a current through a solenoid causes the solenoid to become an
___________________. Turning the current on or off allows us to control the ___________ __________. p384
State two ways we can increase the strength of an electromagnet. State four uses of electromagnets. P384
3. Read p386 – p389 what is the SI unit of magnetic field strength. How can this derived unit be expressed in terms
of other SI metric units. Top p386 Compare the magnetic field strength of a fridge magnet, the earth's amgnetic
field, and a MRI unit. What happens to an electron beam (cathode ray) when a bar magnet is brought near? See
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Page #4
Fig 2 p386 Whenever a charge moves through a magnetic field, the strength of the magnetic force on that charge
depends on the size of the charge in Coulombs, the strength of the magnetic field in Tesla, and what else? To
determine the size of the magnetic force on a charge moving through a magnetic field there is a scalar equation we
can use with no directions or negatives required. State and memorize this equation and know what the symbols
stand for. See top p387 To determine the direction of the magnetic force on a moving charge through a magnetic
field, we use the right-hand rule for a moving charge in a magnetic field, or sometimes called the “Hi” or “palm
rule”. State and memorize this rule. Be careful. This rule applies to positive charges. If the charge is negative,
keep in mind the direction of the magnetic force will be in the opposite direction. P387 Review and redo sample
problems on p388-p389 Do practice Q1-Q4 p390 check answers same page Do Q2-Q10 p391 check answers
p719 Note X means “into the page” and ● means “out of the page”
Read p392 – pp395 The magnetic force magnitude Fmag can be determine using qvBsinΘ, but how do we determine
the magnetic force due to an external magnetic field acting on a straight wire carrying a group of charges moving
through it? Well, we use Fmag =ILBsinΘ. Derive Fmag =ILBsinΘ starting with Fmag = qvBsinΘ (see p393)
Memorize this new equation and what each symbol stands for. Remember this is a scalar equation to determine the
magnitude of Fmag only. Use the right hand rule palm rule assuming conventional current flow from the positive
terminal to negative terminal. Review and redo sample problems on p394. Do Q1 to Q4 p395 answers on same
page. Using a diagram, explain how a loudspeaker works. Do Q1 to Q5 on p396 check answers p719
Read p397 Use your own words to explain what a mass spectrometer is and how it separates atoms and molecules
of different masses. Identify seven applications of the mass spectrometer. Read p398. The mass spectrometer has
a magnetic field which is 90° to the velocity of the charged particle and, according to the right hand palm rule,
produces a magnetic force Fmag which is 90° to both the velocity and magnetic field. Why can't the magnetic force
change the speed of the particle? What is the effect of the magnetic force on the motion of the particle? Using our
expression for centripetal force, derive and memorize the mass spectrometer equation r = mv/qB. Be sure you
know what each symbol stands for. Review and redo sample problems on p399 – p401 Do Q1-Q4 p401 check
answers on the same page Do Q2 – Q6 p404 check answers p719
Read p402 Explain why charged particles from the sun ans stars spiral along the curved magnetic field towards the
poles. What is the Van Allen radiation belt, where is it, and how is it formed? Why is is important to aerospace
engineers? Read p403 What is field theory? Set up a chart to compare electrical, gravitational and magnetic
forces indicating both similarities and differences. Which two fields are actually thought of as a single field?
Read p405 What is an RFID chip? In your own words, explain how it works. State four applications of RFID
technology and why it is better than bar code technology. Read p406- top p407. What is MR fluid? How is this
helpful in constructing buildings in earthquake areas? State four other uses of MR fluids. Read p407-p408 Briefly
outline the controversy regarding electromagnetic fields and human health. Read p408 What is magnetic
resonance imaging (MRI) ? In your own words, outline how it works.
Review:
1.
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A uniform magnetic field of 0.40 T is coming out of this page and a single electron is moving from the bottom of
the page directly up along the plane of the page. The electron has a speed of 3.0 X 10 5 m/s.
What is the magnitude in Newtons for the magnetic force on the electron? (Ans 1.9 X 10-14 m/s )
What is the direction of the magnetic force? ( Ans left along the plane of the page )
A constant magnetic field of 5.0 T acts perpendicular to the direction of conventional current in a straight wire 4.0
m in length. If the magnetic force on the wire is 2.0 N, what is the current in the wire? (Ans 0.10 A)
An 9.1 X 10-31 kg electron is accelerated in a mass spectrometer using a potential difference of 46 Volts. It is sent
into a magnetic field perpendicular to the electron's motion with magnitude 0.0050 T. Find the radius of the
circular path it follows. ( Answer 4.6 mm )
Waves and Light:
1. Read p438 What is visible light? What are some other forms of “light” or “electromagnetic radiation”? Name
three applications involving electromagnetic radiation.
2. Read p440-442 Derive and memorize the universal wave equation and know what each symbol stands for. Define
or explain: periodic wave, wave front, crest, trough, wavelength and symbol, phase, ray approximation, normal,
angle of incidence, angle of reflection, specular reflection, diffuse reflection, law of reflection. What does a wave
transmit? We will soon learn that visible light and all other forms of electromagnetic radiation or “light” such as
radio waves, infrared radiation and X-rays are neither a pure wave nor a pure particle. However, in some
circumstances light can be thought of as a wave and we can use the universal wave equation. Just remember that
all forms of electromagnetic radiation or “light” (radio, microwaves, infrared, visible, ultraviolet, X and gamma
rays) travel at the same fastest speed possible in a vacuum and approximately in air = 3.0 X 10 8 m/s. This speed is
called “c”. For any kind of light we can use this form of the universal wave equation c = f times wavelength.
page #5
3. Strangely, note that light does not require a medium. Now do q1-17 p443 check answers p720-721
4. Read p444-p458 Draw the diagram on p 444 Fig 1 then label and learn the names of incident ray, normal, reflected
ray, refracted ray. Explain and know: refraction, optical density, principle of reversibility, index of refraction,
n=c/v including symbol names, how the speed of light changes going from air to an optically more dense medium,
angle of incidence, angle of refraction Derive Snell’s law equation and memorize. Derive and memorize the
equation relating index of refraction and wavelength p447. Review sample problems p448 – p449 do Q1 to Q6
p449 check answers same page Define dispersion and sketch the diagram on p450. Which wavelength of light
gets refracted more, red or blue? What is the angle of deviation? Review sample problemp451 –p452 then do
Q1,2,3 p452 What is total internal reflection and under what conditions does it occur? What is the critical angle
and the equation we use to calculate it? Explain how total internal reflection is involved in periscope design and
fibre optics cables. Review sample problems p457 Do Q3-Q10 p458 check answers p721
5. Read p459 –p463 Define diffraction of waves. What happens to the amount of diffraction if.. a) the opening is
decreased ? b) the wavelength is decreased? Review tutorial #1 p461. How does the ratio of wavelength to
opening width help us predict the amount of diffraction? Do Q1, Q2 on p461. Define or explain: wave
interference, constructive interference, destructive interference, coherent waves, node, nodal line What happens if
two waves are.. a) in phase? b) 180 degrees out of phase?
6. It is now known that light is not a pure wave nor a pure particle, although the two models of light are helpful in
predicting its behaviour. Light has what is known as “wave-particle duality”. When we do some experiments,
light behaves like a particle. When we do other experiments it behaves like a wave. Read p470 – p476 What
model of light, wave or particle, did these scientists believe described the nature of light? a) Grimaldi b) Newton
c) Huygens d) Young Define or explain: Huygen’s principle, rectilinear propagation For both Newton’s
particle theory of light and Huygen’s wave model of light, outline how well their theory explained the following
phenomena: a) rectilinear propagation b) diffraction c) reflection d) refraction
7. Read p526 – p530 What is electromagnetic radiation and give some examples? What is Faraday’s law? What is
Maxwell’s hypothesis? What are Maxwell’s four key ideas associated with his famous four key equations of
electromagnetism? In 1864, Maxwell used his equation to predict something that was later verified by Hertz in
1887. What was his prediction? How can an electromagnetic wave be produced? Sketch a diagram of an
electromagnetic wave or electromagnetic radiation. What are the three main properties of an electromagnetic
wave? Do electromagnetic waves need a medium like water waves? In a vacuum and approximately in air, what is
the speed of all form of electromagnetic waves? What is the symbol for this speed? How are electromagnetic
waves classified? If the frequency of an EM wave increases, what happens to the wavelength? What is the
electromagnetic spectrum? List all the names of the electromagnetic waves from highest to lowest frequency. For
electromagnetic waves that we can see, or “visible EM waves”, which colour has the a) longest wavelength? b)
shortest wavelength? What is the range of wavelength values in nm for the visible light spectrum? Outline the
characteristics of all the different EM waves and how they are used in society. Review and re-do sample problem
#1 on p530 then do Q1-Q4 on p530 check answers on the same page. Do Q1-Q4 Q6-Q7
Special Relativity:
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Read p574 to p579
In the mid-nineteenth century, James Maxwell correctly explained most of the behaviour of light as a combination
of oscillating electric and magnetic fields or travelling “electromagnetic waves”. However, by 1900, it was known
that Maxwell's ideas could not explain two observed phenomena. In addition, there was no detection of an entity
which seemed necessary to support the motion of Maxwell's electromagnetic waves. Briefly state these three
“problems” in Maxwell's theory at the turn of the twentieth century. top half p574
Define: frame of reference, inertial frame of reference, principle of relativity
In your own words, use the billiard table experiment in a railway car example to explain the terms in question #3.
How must the railway car move to become a “non-inertial” reference frame, where Newton's first and other laws
do not seem to predict what is happening? bottom half p574, p575
Before the Michelson and Morley experiment in 1887, most physicists believed in an “ether”.
Explain why they thought an “ether” existed and describe some of its properties. p576
If you are inside an airplane, pouring coffee into a cup or playing “catch” with someone would seem exactly the
same to you whether or not the plane is at rest or moving at constant velocity. If all the plane window blinds are
closed, there would be no way to tell if the plane is at rest or constant velocity. Thus, in these “inertial reference
frames”, Newton's laws that predict the motion of coffee and moving balls do not change. Newton's laws remain
“invariant”. However, if the ether exists, and “c” is the speed of light waves with respect to the ether, does the
speed of light remain the same in all inertial or constant velocity reference frames? Explain why or why not. Use
Fig. 3 on p576 to help you answer this question.
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Page #6
Did experimental evidence support the idea that the speed of light changed with the velocity of the reference
frame? If not, what did this say about the presence of the ether? What two experiments provided a ”null result”
for the detection of the “ether”? top half of p577
Einstein believed the principle of relativity should apply for all laws of physics, not just Newton's laws. He
believed Maxwell's theory of electromagnetism and the speed of light waves in a vacuum should also remain the
same or be “invariant” in all inertial reference frames at a value “c” = 3.0 X 10 8 m/s or 300,000 km/s. Reasoning
along these lines of thought, and the lack of evidence for the “ether”, prompted Einstein to propose two
“postulates” or statements assumed to be true without absolute proof. State Einstein's two postulates. bottom half
page 577
In the miracle year of 1905, Einstein published his Special Theory of Relativity. In Einstein's general statement
of this theory, he wanted to get across the idea that Newton's laws and Maxwell's laws of electromagnetism are
valid in all inertial reference frames. He correctly believed there is no way of determining whether a reference
frame is at rest or at constant velocity. State the main conclusion of Einstein's theory encompassing these
aforementioned ideas as a result of the combination of his two postulates. middle of page in a blue box p578
If you can understand and be able to answer these questions, you can move on to 11.2 on p580.
a) p578 Q3, Q9 Check answers p722
b) A rocket car in space is moving at 100,000 km/s [to the moon] with respect to the moon. As it moves, it shines a
headlight forward moving directly toward a light speed detector fixed to the moon. What speed does the detector
display as the speed of light from the rocket's headlights. Check answer: “c” or 300,000 km/s not 400,000 km/s as
common sense might dictate!
Read p580 to 585 but ignore or skip the two lines after (Equation 1) in the middle of p582. It start with “We Know
that... and ends with ...light, we get. These two lines are incorrect.
Be able to derive and know the time dilation formula Δtm = Δts / (1 – v2/c2)1/2 using the light clock idea with
observer 1 and observer 2.
a) Despite the simplicity of Einstein's special theory of relativity statement, the consequences of his theory defy
common sense and contradict Newton's ideas of absolute time and the idea that there is a fixed absolute rest frame
called the ether. Einstein's new theory put all inertial or constant velocity frames on an equal footing. Much to the
chagrin of Newton, the speed of light in a vacuum remains constant or invariant as measured in two different
inertial frames, but “time duration” of a journey or event measured in two inertial reference frames moving with
respect to each other will give different results. This relates to the idea of “time dilation”. Define time dilation and
explain why it happens as a result of Einstein ideas.
b) What does Δtm and Δts stand for? Which of these symbols stand for proper time? Define proper time. P583-584
c) Before you go over sample problem #1 p584, keep in mind that heartbeat is a frequency, not a period or time
unit. This is why the book took the reciprocal of heartbeat frequency to get a time unit or period before substituting
into the time dilation formula. Remember T=1/f . Not all questions give frequency but give time directly. Also
note, when substituting for v in the time dilation formula, do not use MKS units but v in terms of c like v = 0.90c.
Solve Q1 to Q5 on p585. Check answers on the same page.
What does the graph on p 583 tell us about how close Δtm is to Δts even for our fastest satellites with v = 3 x 103
m/s or 0.00001c ? At what speed relative to c do we notice a factor of two difference between Δt m and Δts ? Check
answer 0.85c Do you think we have to worry about time dilation in car and plane trips in everyday life? Why or
why not? P583
Experiments have been set up to verify the validity of the special theory of relativity. In the mid twentieth century,
physicists studied “muons”, a kind of heavy electron that eventually decays to a stable electron in 2.2 μs when it is
at rest. This is its “proper time”. Experiments were done in “particle accelerators” to speed these muons up to 1.8
X 108 m/s or 0.60c. The muons decay time was measured and found to have increased to 2.8 μs. Use the time
dilation equation and verify for yourself that this result is in accordance with Einstein's theory.
Read p586 Outline how the Hafele-Keating experiment in 1971verified Einstein's special relativity time dilation.
Even though identical clocks were used, can you explain why the eastbound jet was the slowest clock compared to
the other two clocks? top half of page 586 then try Q4 on p587
It should be noted that a more complicated theory of gravitation that Einstein developed in 1915 is called general
relativity and looks at light speed invariance in “accelerating” or “non-inertial” reference frames. Einstein
discovered that a stronger gravitational field makes clocks run slower. Time dilation due to special and general
relativity must both be taken into account when designing GPS systems. Briefly explain why GPS systems need to
take special relativity into account. bottom half p586
Do Q6,7 p587 Check answer p722
Read p 588 to p591.
Explain the difference between Lm and LS. Which symbol represents proper length and which symbol represents
relativistic length. Define proper length and relativistic length. P588 and p589
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page #7
Using observer 1 on a railway car and observe 2 at rest, derive and know the length contraction formula. P588-589
How does relativistic and proper length compare for car and plane speeds here on earth? Why? top p590
Define and know length contraction. Along what axis does length contraction happen? Middle of p590
Noting that we substitute v as a speed relative to c, not as an MKS value, review sample problem #1 on p590.
Do Q1,2 and 3 on p591 Check answers on same page.
Read about muons p591 Muons, as mentioned before, have a lifetime of 2.2 μs. (not 2.2 ms as mentioned in the
book) These unstable particles are born in our upper atmosphere when charged particles like protons and electrons
from the sun and stars ram into upper air molecules. Some of them can move at close to light speed. Imagine you
are riding along with one of these fast muon particles moving toward the earth's surface. To you, the muon is at
rest and can only live for 2.2 μs. This is not long enough for you and the muon to make it 4800 m to the earth's
surface, yet, we observe muons on the earth's surface. Use length contraction to explain why. Page 591
A spaceship moves towards a star. Use the graph on p590 to determine approximately how fast the spaceship has
to move relative to the star so that the distance measured by the spaceship to the star is half the distance the
spaceship measures when it is at rest relative to the star. Check answer: about 0.85c
Read Relativity of Simultaneity from the bottom of p591 to p593
Define simultaneity, then use a moving observer 1, an observer 2 at rest, and a pair of lightning bolts to explain
why simultaneous events in one inertial reference frame is not necessarily simultaneous in another inertial
reference frame, especially when the frames are moving at near light speed with respect to each other. p591
Read about the Twin paradox p593-p594
Define Twin Paradox. Note that it is the astronaut twin that ages less, even though, to him, his sister is moving
away from him at 0.90c and her clocks should be moving more slowly. The book fails to mention another reason
for this. In the beginning of the trip, the astronaut's spaceship or frame of reference must accelerate from rest on
earth to 0.90c. For a brief period of time, the astronaut 's frame of reference is a non-inertial or accelerating frame
of reference. Einstein's general theory or relativity tells us that any acceleration mimics a gravitational field, and
time runs more slowly for larger gravitational fields. The book does mention there is another acceleration due to a
180° turn, which again means time runs slowly for him. It is the astronaut's spaceship and reference frame that
must fire rockets to speed up and turn, not the girl's earth frame of reference which remains at rest through the
entire astronaut's journey. The earth does have a very small acceleration due to revolution about the sun and
rotation about its axis, but this is a very small effect. The book does describe another way to reconcile the
imagined twin paradox using length contraction. Briefly describe how length contraction reconciles the twin
paradox. Also, define space-time. page 594
Read about Relativistic Momentum, Universal speed limit p594-596 Define relativistic momentum
Look at the graph on p594. For speeds less than 0.1c, how does relativistic momentum according to special
relativity compare to Newtonian or classical momentum p=mv? For speeds between 0.1c and c, how does
relativistic momentum according to special relativity compare to Newtonian or classical momentum p=mv?
Again look at the asymptote on the graph p594. According to special relativity, there appears to be a speed limit
for objects moving with a certain momentum. What is that speed limit? According to Newton or classical physics,
is there a speed limit for objects moving with a certain momentum? P594
Derive the equation for relativistic momentum and memorize it. What do the symbols m and p stand for? Using
the equation, what happens to an object's mass or momentum as a net force cause it go faster and faster near the
speed of light “c”? Define relativistic momentum, relativistic mass, and rest mass p595
Review tutorial 2 on p595-p596. Which formula is more accurate when calculating momentum, Newton's p=mv or
Einstein's p=mv/(1-v2/c2)1/2 ? Under what circumstances is Newton's momentum equation perfectly adequate to
use? Do Q1 to Q4 p 596 Check answers same page Do Q1,2 Q4 to Q6, Q8 p597 check answers p722
Read p598-p602 How does the mass of a body change as speed increases?
State and know the relativistic mass equation and what m and mr stands for. State and know the formulas for rest
energy, total (relativistic) energy and relativistic kinetic energy and what all the symbols stand for.
Define in words: rest energy, relativistic kinetic energy, relativistic total energy, conservation of mass-energy
page 598-599
Look at the graph on p599. At what speeds are the relativistic kinetic energy formula and Newton's kinetic energy
formula Ek=mv2/2 almost the same? Check answer: about less than 0.1c
What kinds of technology are involved in converting mass into energy?
Review tutorial #1. Define the electron-Volt. Note it is a unit of energy. What is the conversion factor between
electron-Volts and Joules? Do p602 Q1-Q4 Check answers on same page Do Q1-Q12 p603 Check answers p722
Now try some review questions:
As measured from earth, a star X, which is not moving with respect to the earth, is 8.0 light years away. Note that
a “light year” is actually a distance unit. A spaceship initially passes by the earth moving at 0.95c with respect to
the earth, moving toward star X. At that instant the pilot of the spaceship starts her ship clock to the mark the start
page #8
of her journey to star X. When the ship arrives at star X, the pilot stops the ship clock and notes that 2.63 years
have elapsed.
a) What is the time duration of the spaceship's trip as measured by an observer on the earth? Ans 8.4 years
b) What distance in light years does the pilot measure from earth to star X? Use two methods. Ans 2.5 light years
c) If the pilot of the spaceship is 50.0 kg as measured on a device in the spaceship, what would an observer on the
earth measure the pilot's mass to be? Ans 160 kg
d) What is the pilot's rest energy? Ans 4.5 X 1018 J
e) According to an earth observer, what is the pilot's total relativistic energy? Ans 1.4 X 1019 J
f) According to an earth observer, what is the pilot's relativistic kinetic energy? Ans 9.9 X 1018 J
Quantum Mechanics
1.
2.
Read p614
Do the laws of Newtonian mechanics apply to the microscopic world? Explain. What do the innovations of
computer and digital technology rely on? State two other applications where knowing the laws of the very
small is important.
3. Read p616 to p618
4. In the late 1800’s, did experiments indicate that Newton’s and Maxwell’s theory fully described the world of
the atom and subatomic particles?
5. What is the physics term that describes the smallest bundle or amount of energy we can have in the sub-atomic
world? Define quantum theory. According to the classical physicists Newton and Maxwell, how can energy
be carried from place to place? Using diagrams, compare the results of pure waves moving through a doubleslit apparatus as opposed to pure particles. What is the energy of a pure wave described by? In the tiny world
of the atom, unlike the macroscopic world of trucks and planes of Newton and Maxwell, there is no such thing
as a pure particle or a pure wave. For example, electrons were thought of as being a pure particle in the early
1900’s. However, what happens when electrons are sent through a double-slit apparatus? How do electrons
behave as both a wave and particle in this experiment? What is wave-particle duality? What are the two main
properties of the wave-particle behaviour of matter?
6. Read p620-p631
7. Gilbert Lewis, a chemist, coined a physics term for “particles of light” back in the 1920’s. What is the term
called? Due to the results of Young’s double-slit experiment in 1800, what model of light did most nineteenth
century (1800-1900) scientists use to describe light behaviour? What experiment in the 1880’s forced
scientists to rethink this model to describe and predict light’s behaviour? What does the term work function
mean? Why do different metals have different work functions? What is another very small unit of energy that
physicists use? What is the conversion factor of this unit in terms of Joules? What equation can we use to
determine the amount of energy in Joules that an electron has when it is accelerated through a potential
difference in Volts? What is the photoelectric effect? What is threshold frequency? What two difficulties
arose from using a pure wave model to explain the photoelectric experiment results? What new theory
prevailed as the accepted explanation? In 1905, what proposal did Einstein put forward to explain this
photoelectric effect? Describe the properties of a photon of light, including the equation for the packet of
maximum kinetic energy that it carries. State what each symbol stands for. What is Planck’s constant and
what is its value in SI units? Use a conservation of energy argument to derive Einstein’s 1921 Nobel prize
winning linear equation for the photoelectric effect. Memorize this formula, the symbols and t each symbol
stands for. Sketch a graph of maximum kinetic energy of electrons vs light frequency and indicate where
threshold frequency is on the graph. In what two ways did Einstein’s quantum explanation predict exactly
what happens when light strikes a metal and how are his ideas superior to the classical viewpoint that light is
a pure wave?
8. Review and redo tutorial #1 p623. Do questions 1,2 p624 Check answers same page
9. Starting with p = E/c, derive the momentum of a photon equation p = h/(wavelength). Memorize the equations
on p 624 and know what all the symbols mean. What experiment showed that light does have momentum?
Describe the Compton effect. What kind of “light” was used? What model of light, particle or wave, is used
to describe the Compton effect? What two quantities are “conserved” or “stay the same” in Compton’s
experiment? What equation is used to find the energy of a photon? Remember to solve for frequency by using
the universal wave equation f =c/(wavelength) but wavelength has to be in meters not nanometers. Re-do and
review tutorial #2 on p625-p626 Do questions #1-3 on p626 check answers same page.
10. Read p626-p631When a photon of electromagnetic radiation comes in contact with matter, there are five
possible interactions. List these possible interactions. Note that pair creation involves converting energy into
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Page #9
mass Using the equation E =mc2. What is a blackbody? What is blackbody radiation? Note that ideal
blackbodies also emit the same amount of radiation energy as they absorb. Give an example of an
approximate blackbody. Sketch a blackbody radiation intensity vs wavelength curve for high and low
temperatures. Describe the shape of the curve and how it changes as the temperature of the blackbody is
increased. Note, when we heat a metal bar in a furnace, the metal bar will first emit most or the peak radiation
light in long wavelength red light, then, as the furnace is heated, the peak blackbody radiation emitted will be
in the blue and ultraviolet (invisible)short wavelength part of the spectrum. Most scientists before 1900
believed that light can be modelled as a pure wave as predicted by Young’s double slit experiment and
Maxwell’s EM wave theory. However, this classical view of “light” made the wrong prediction about the
shape of the blackbody radiation curve and what happens to the intensity of the blackbody radiation for high
frequencies. What is this wrong prediction? What is the ultraviolet catastrophe? In 1900, Planck resolved the
“ultraviolet catastrophe” to predict exactly what the blackbody radiation curve looks like in nature. What is
Planck’s hypothesis? What is Planck’s equation for the energy of vibrating atoms in a blackbody? Memorize
it and know what the symbols represent. Note Planck used the term “quantum” or “parcel” of energy. Thus,
for the first time, a theory of the micro-world was put forward that involved discrete and non-continuous
packets or quanta of energy. Thus energy of vibrating atoms could take on only whole number multiples of
“hf” but not ½ hf or 5/6hf. It was as if atoms and light were on a an energy ‘staircase”. Just as we can’t be
standing between the third and fourth step, only on the third step or on the fourth step, atoms are only allowed
certain discrete or ‘quantized” energy values. They can have energies of 1hf, 2hf, 305hf, but not 5/7hf. This
“discreteness” idea is a common theme in the modern quantum theory of the atom and light. Planck did not
understand why his new theory worked. How did Einstein help Planck to answer “why” his theory worked?
Read about Wien’s law p628. State the equation for Wien’s law and what the symbols mean. How does an ear
thermometer work? Review and re-do tutorial #3 on page 629. Do Q1-Q3 on p629 Check answers on same
page. List two experiments that show the particle nature of light and one experiment that shows the wave
nature of light. What is this dual nature of light called? Do Q1-Q6 on page 631, then check answers on p723
Read p632-p639 . What is deBroglie’s hypothesis? What is deBroglie’s equation for determining the
wavelength of a particle? State what each symbol stands for and memorize. What is the debroglie
wavelength? What is a matter wave? What particle was tested to see if it had wave characteristics and its
associated deBroglie wavelength? Describe the 1927 Davisson-Germer experiment. How did this experiment
show that electrons can behave like a wave? Review and re-do tutorial #1 on p633. Do Q1-Q4 on p634
Check answers same page. Why can’t we see or measure the wavelengths of large objects like baseballs?
Fill in the blanks: In the double-slit diffraction of electrons experiment, electrons arrive at the screen as
___________________ but the spot on the screen where they arrive is determined by _____________ like
interference. Is it easy to interpret the results of electron diffraction through double-slits? What is the collapse
interpretation of the electron double-slit experiment? What is the pilot wave interpretation of the electron
double-slit experiment? What is the many worlds interpretation of the electron double-slit experiment? What
is Bohr’s Copenhagen interpretation of the electron double-slit experiment? Fill in the blanks: Much like
Newton’s laws describe the motion of large objects, _____________________’s equation developed in 1925
(Nobel prize 1933) help determine the _______________________ of small particle-waves like the electron
and photon related to the ___________________________ for particle-waves to take on any possible path or
to show up at any possible location on the detection screen in the double-slit experiment. Wavefunctions of
sub-atomic particles are similar to _______________________ waves in a box. Electrons with different
kinetic energies will have different _______________________. A wavefunction of a particle determined by
Schroedinger’s equation allows the calculation of the ____________________ of finding the electron at
different locations in space. See p636 Now read p637-p638 Note that quantum mechanics never deals with
predicting exactly where and exactly how fast a sub-atomic particle are moving at an instant in time, only
probabilities. Yet, quantum theory is still the most accurate predictor of the behaviour of small particles and is
needed for our smart phones, GPS networks and computer systems. In the late 1920’s, Heisenberg extended
this idea of “measurement limitations” of sub-atomic particles by formulating his famous “Uncertainty
Principle”. Note that this principle has nothing to do with accuracy or precision of the measuring instruments,
but a statement that nature itself is not precise but “jittery”. In your own words, explain what the Heisenberg
Uncertainty Principle is and state the inequality we use to describe this principle. Memorize the inequality and
what the symbols mean, then use the inequality to describe how the uncertainty in measuring the momentum
of a particle changes as the uncertainty in measuring the position of a particle decreases. List four
applications of wave-particle duality in our modern world. See p 638 Do Q1-Q3 p639 check answers p723
Page #10
13.
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Read p644 – p653. Describe Rutherford’s 1909 gold foil experiment. How did an unexpected observation of
this experiment lead to Rutherford’s new model of the atom? Describe Rutherford’s model of the atom. How
did Rutherford explain how electrons orbit around the nucleus? According to the classical theory of Newton
and Maxwell, what is the major problem with Rutherford’s planetary model of the atom? In 1912, Bohr
modified Rutherford’s model by introducing the quantum idea of “discreteness” and “Planck’s quanta” and
the new quantum notion that certain quantities could only take on whole-number multiples. What quantities
could only take on certain whole-number values in Bohr’s model of the atom? How did Bohr’s model get
around the problem of electrons spiralling into the nucleus? How did Bohr explain how an atom could absorb
and emit photons of light? Why was Bohr’s model only partially successful? Ten years after Bohr put forward
this part quantum and part classical model of the atom, deBroglie’s matter waves idea helped explain why
Bohr’s model explained why electrons could be found in only certain orbits. How? Review and re-do tutorial
#1 p646 then do Q1, Q2 p647
Read p647-p653. In the early 1930’s, Paul Dirac combined quantum theory with special relativity relativity
Theory and predicted the existence of a new particle. This particle was soon detected when cosmic rays from
space collide with upper atmospheric air molecules. What is the new particle called and describe its
properties? Compare the positron with the electron. What are the symbols for both? A positron is an example
of antimatter. What is antimatter? Give two more examples of antimatter particles. What are the symbols for
antineutrons and antiprotons? Protons and neutrons are made up of ___________ and antineutrons and
antiprotons are made of anti- _____________. What happens when a positron and electron meet? What
conservation law must hold during this reaction? Why do you think the universe has an imbalance of more
normal matter than antimatter?
Read p648 – p651. We used to think that neutrons and protons are fundamental building blocks of the atom.
Because of collision experiments in billion-dollar accelerators, we now know that protons and neutrons are
composed of __________________. The charge on a quark can be either be ________ or _________. The
charge on an antiquark can be either be__________ or ________. Any particle made of quarks or anti-quarks is
a member of the __________________ family. The rest of the sub-atomic particles of normal matter or
antimatter are part of the ________________ family which includes the electron and the positron and are not
made up of quarks. The _________________ model is the current model of fundamental particles of quarks
and leptons and how they interact with each other. Define and memorize the definitions of: quark, hadrons,
leptons, standard model. Hadrons like the proton, neutron and sigma plus are made of __________ quarks. A
proton is made of two _____ quarks of charge _______ and one _____ quark of charge ______. Use quark
charge to explain how the charge on a neutron totals zero charge. There are only __________ flavours of
quarks. State the symbols and charges of the different quark flavours. Hadrons made up of three quarks like
protons and neutrons are called __________________. Hadrons like the pion or kaon made of one quark and
one antiquark are called _____________________. The two most important hadrons are the ____________
and the ______________. Since quarks are charged, there is an _______________________ force between
them and since they must attract in the nucleus of the atom, there is a ________________ force between them.
What are the six fundamental leptons? What are the three pairs of leptons? Compare the mass and charge of
the electron, muon, and tau particle with the electron neutrino, muon neutrino, and tau neutrino. Which lepton
is stable? What is a peculiar property of neutrinos? Write the equation that describes how a lepton is involved
in the decay of an isolated neutron. What reaction in the sun produces neutrinos? Which three forces are
involved when explaining the motion of quarks and leptons? What does the strong force do? What does the
weak force do? What is the electromagnetic force responsible for? Together, what do physicists call quarks
and leptons together? The standard model of fundamental particles also includes force-carrying particles called
________________. Which boson carries or “mediates” the electromagnetic force “between charges? Which
boson carries or “mediates” the strong force between quarks and how many types of these bosons exist? Which
three bosons carries or “mediates” the weak force between leptons or leptons and quarks? Define: fermion,
boson, and gluon. Use a game of catch to explain how bosons ‘carry’ or ”mediate” forces between fermions.
Copy table 6 and table 7 into your notebook and learn all the particles of the Standard Model. There is another
Standard Model particle that was predicted by Standard Model theory. At the time of writing of this book, this
particle was not detected at the nine-billion dollar and largest particle accelerator called the Large Hadron
Collider near Geneva , Switzerland. (LHC) However, on July 4, 2012, this particle was discovered by the
physicists of the LHC. It was a major discovery in physics. What is this particle called and what is its role?
Explain what is meant by “Theory of everything”.