Download Laws of Thermodynamics

KHS Physics Spring Final Review Spring 2012
1. KE is energy of motion. PE is energy of position
2. KE = ½ m v2 and PE = mgh
3. Thermal Energy- is the sum of the kinetic and potential energy of all the
molecules in an object.
4.
Heat transfer problems
Q = m c T
Where
m = mass (kg)
c = specific heat of the material
T = Tf - Ti (change of temperature in C
Change of Phase problems
Q = mHf
Q =mHv
Where
m = mass (Kg)
Hf = heat of fusion
Where m = mass (Kg)
Hv = heat of vaporization
5.
The total potential and kinetic energy of all microscopic particles in an object make up
it's thermal energy.
6. Joules
7. a. Solid phase a
b. Liquid phase c
c. gas Phase e
d. Melting b
e. Boiling d
8. Hot to cold
9. Three methods of heat transfer:
a. Conduction- The transfer of thermal energy through matter by the direct
contact of particles.
Examples: Touching a stove and being burned
-Ice cooling down your hand
-Boiling water by thrusting a red-hot piece of iron into
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b. Convection- the transfer of energy in a fluid by the movement of the heated
particles.
Examples: Hot air rising, cooling, and falling (convection currents)
-An old-fashioned radiator (creates a convection cell in a room by emitting warm air
at the top and drawing in cool air at the bottom).
c. Radiation- The transfer of energy by electromagnetic waves.
Examples: Heat from the sun warming your face
-Heat from a lightbulb
-Heat from a fire
10.
a. Thermal conductor- A material that conducts heat well and quickly
Examples: metals
b. Thermal Insulator- A material that does not conduct heat well
Examples: wood, brick plastics
11.
Specific heat - the amount of energy that must be added to raise the temperature of one
kilogram of the material one degree Celcius
Q = m c T
Where
m = mass (kg)
c = specific heat of the material
T = Tf - Ti (change of temperature in C
Units of c is J/kgC°
12.
Temperature -measure of an object’s kinetic energy; temperature measures how hot or
how cold an object is with respect to a standard
units C°, K and F°
13.
Laws of Thermodynamics
First Law OF THERMODYNAMICS – HEAT ADDED TO A SYSTEM = INCREASE IN INTERNAL
ENERGY + EXTERNAL WORK DONE BY THE SYSTEM: Q = U + W
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SECOND LAW OF THERMODYNAMICS- NATURAL PROCESSES GO IN A DIRECTION THAT
MAINTAINS OR INCREASES THE TOTAL ENTROPY OF THE UNIVERSE.
14. Density

Density is a physical property of matter that is defined as the ratio of an
object's mass to its volume.
We can calculate density using the formula:
Density= Mass/Volume
Wave Properties and Behaivor
Matching
15. Period g
16. Reflection h
17. Refraction i
18. Wave k
19. Amplitude a
20. diffraction c
21. Interference f
22. frequency d
23. hertz e
24. wavelength l
25. wave motion m
26. crest b
27. trough j
28. Reflection – the bouncing back of a wave. Uses: Radar, echo, mirrors
29. Refraction
Refraction of waves involves a change in the direction of waves as they pass from one
medium to another. Refraction, or bending of the path of the waves, is accompanied by a
change in speed and wavelength of the waves.
Uses: eye glasses, cameras and fiber optics
30. Identify parts of a wave
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Parts of a wave
Crest
Trough
Wavelength
Compression
Rarefaction
31.
Longitudinal Wave
Transverse Wave
Transverse wave- Particles move perpendicular to the direction of the motion of the
wave.
Longitudinal wave- Particles move parallel to the direction of the wave.
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32. Electromagnet Spectrum
All electromagnetic waves travel at the speed of light in a vacuum.
A. A standing wave – also known as a stationary wave – is a wave that remains in
a constant position.
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33.
Wave type
Electromagnetic
Mechanical
speed
Speed of light
Medium
Can travel in
vacuum
Need medium
Much slower
depends on medium
Example
Light
Water wave
34. Frequency of a wave is inversely proportional to the wavelength.
35. Wave speed is independent of amplitude.
36.
Given: T = 4 s and λ = 3 m
a. f = 1/T, thus f = ¼= .25 hz
b. v= fλ thus, v= 3x .25 = .75 m/s
37.
f = 500 hz, λ = .1 m
v = f x λ v= 500 x .1 = 50 m/s
v = d/t
t = d/v t = 2000m/ 50 m/s = 40 s
38.
Sound- Sound is energy that is produced by the compression and rarefaction of matter. It
travels as a longitudinal wave.
39. define
a. Pitch- the frequency of the wave.
b. Loudness-The amplitude of sound
c. Resonance- to vibrate at the same frequency, which increases the
amplitude of the wave.
d. Doppler Effect- change in frequency due to relative motion of source and
detector.
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40.
You hear the high pitch of the siren of the approaching ambulance, and notice that its
pitch drops suddenly as the ambulance passes you. That is called the Doppler effect.
41. Volume is directly proportional to the amplitude of the wave.
42. See above
43. Light is a transverse wave that travels at 3 x 108 m/s in a vacuum.
44.
The differences between light and sound are as follows:








Light can be considered to be made of waves as well as particles. Sound is only a
wave. It does not show particle nature.
Light waves are electromagnetic waves while sound waves are mechanical waves.
Light waves are transverse while sound waves are longitudinal.
Light waves can travel in vacuum. Sound waves require a material medium to
travel, and hence, cannot travel in vacuum.
The speed of light in a medium is constant. The velocity of sound waves can
change.
In sound waves, the particles of the medium actually oscillate. In a light wave, the
electric and magnetic vectors oscillate.
Light waves can be polarized, but sound waves cannot.
Light waves travel much faster than sound waves. The speed of light is a physical
constant. Its value is exactly 299,792,458 metres per second in vacuuum. The
speed of sound is 343 metres per second in dry air at 20°C.
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
And finally, a simple one - you can see light while you can hear sound.
From
http://wiki.answers.com/Q/What_is_the_difference_between_light_waves_and_sound
_waves
45.
34. Electromagnet Spectrum
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46. v= λ x f
Light with a lower frequency will have a longer wavelength. Frequency and wavelength
are inversely proportional to each other (i.e. as one increases, the other decreases and
vice-a-versa). The product of frequency and wavelength is the speed of light.
47.
Snell’s law: light traveling from medium to medium
ni sinӨi = nr sinӨr
1 sin49 = 1.76 sin θ
θ= sin-1 (sin49/1.76) = 25.39°
48.
Total internal reflection- Occurs when light passes from a more optically dense
medium to a less optically dense medium at an angle so great that there is no refracted
ray.
49.
Electric charge is a physical property of matter which causes it to experience a force
when near other electrically charged matter. Electric charge comes in two types, called
positive and negative.
Unit of charge- 1 Coulomb
1 Coulomb = charge of 6.25 x 1018 electrons
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50. Charges are not created but separated. (i.e. electrons can be removed from or
added to atoms)
An increase or decrease in the number of electrons in an object gives it an electrical
charge. When an object gains electrons, it becomes negatively charged. When it loses
electrons, it becomes positively charged.
51.
Two positively charged substances, or objects, experience a mutual repulsive force, as do
two negatively charged objects. Positively charged objects and negatively charged
objects experience an attractive force.
52.
Coulomb’s Law- The magnitude of the force that a tiny sphere with charge q
exerts on a second sphere with charge q’, separated by a distance d.
F = k q q’/ d2
where k = 9 x 109 Nm2/C2
q,q’- charges in Coulombs
d – distance in meters
F – Newtons
53. Variables that affect electrical force
Charge- directly proportional
Distance- inverse square law
54 Electric field – Property of space around a charged object that causes forces on
other charged objects.
An electric field is a vector with both magnitude and direction.
The direction of the electric field is the direction of the force on the positive
test charge.
Electric field lines- lines representing the direction of the electric field.
Note: the spacing between the lines indicates the strength of the electric
field. The field is strong where the field lines are closed together
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55.
A series circuit is a circuit in which resistors are arranged in a chain, so the current has
only one path to take. The current is the same through each resistor. The total resistance
of the circuit is found by simply adding up the resistance values of the individual
resistors:
equivalent resistance of resistors in series : R = R1 + R2 + R3 + ...
56.
A parallel circuit is a circuit in which the resistors are arranged with their heads
connected together, and their tails connected together. The current in a parallel circuit
breaks up, with some flowing along each parallel branch and re-combining when the
branches meet again. The voltage across each resistor in parallel is the same.
The total resistance of a set of resistors in parallel is found by adding up the reciprocals
of the resistance values, and then taking the reciprocal of the total:
equivalent resistance of resistors in parallel: 1 / R = 1 / R1 + 1 / R2 + 1 / R3 +...
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57.
The total resistance of the circuit is found by simply adding up the resistance values of
the individual resistors:
equivalent resistance of resistors in series : R = R1 + R2 + R3 + ...
The total resistance of a set of resistors in parallel is found by adding up the reciprocals
of the resistance values, and then taking the reciprocal of the total:
equivalent resistance of resistors in parallel: 1 / R = 1 / R1 + 1 / R2 + 1 / R3 +...
58.
Need values of resistors.
Would use I = V/R
59.
Use P = VI
P = 12x5 = 60 watts
60.
V = IR
V = 5x 2.4 = 12V
61.
P = VI
If power is held constant, then Voltage and current are inversely proportional.
62.
All magnets are caused by the movement of electrons. No moving electrons = no magnet.
In a permanent magnet, several adjacent electrons have the same spin - they form a
magnetic domain.
63.
A permanent magnet retains its magnetic properties for a long time.
Temporary magnets are those that simply act like permanent magnets when they
are within a strong magnetic field.
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64. Magnetic fields
1. Magnetic field- Space around a magnet throughout which magnetic force
exists.
2. Iron filings around a magnet can represent magnetic field lines.
3. The greater the number of field lines, the stronger the magnetic field
4. The direction of the magnetic field lines is defined as the direction to
which North pole of a compass points when it is placed in the
magnetic field.
5. The field lines come out of the magnet at its North pole and enters the
magnet at its South pole.
6. The magnetic lines are most concentrated at the poles where the magnetic
field is the greatest.
65. The magnetic lines are most concentrated at the poles where the magnetic field is the
greatest.
66.
An electromagnet is a type of magnet whose magnetic field is produced by the flow of
electric current. The magnetic field disappears when the current ceases.
67. Increase the number of turns or increase the current.
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68.
The photoelectric effect refers to the emission, or ejection, of electrons from the surface of,
generally, a metal in response to incident light.
Analysis of data from the photoelectric experiment showed that the energy of
the ejected electrons was proportional to the frequency of the illuminating
light. This showed that whatever was knocking the electrons out had an
energy proportional to light frequency. The remarkable fact that the ejection
energy was independent of the total energy of illumination showed that the
interaction must be like that of a particle which gave all of its energy to the
electron!
69.
The wave particle duality principle of quantum physics holds that
matter and light exhibit the behaviors of both waves and particles,
depending upon the circumstances of the experiment.
70.
Phenomenon
Can be explained in terms of
waves.
Can be explained in terms of
particles.
Reflection
Refraction
Interference
Diffraction
Polarization
Photoelectric
effect
71.
E = Hf
As frequency of light increases, the energy of light increases.
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72.
E= mc2
Einstein
73.
The equation E = mc2 indicates that energy always exhibits mass in whatever form the
energy takes.[3] Mass–energy equivalence also means that mass conservation becomes a
restatement, or requirement, of the law of energy conservation, which is the first law of
thermodynamics
74.
As a part of the medical subspecialty of Nuclear Medicine, various diagnostic procedures
make use of a small amount of a radioactive isotope, usually injected into the patients
bloodstream for the purpose of imaging some part of the body. The useful radiation from
such isotopes is usually gamma rays, which can be detected outside the body. These
gamma rays can be used to image an internal organs or structures.
75.
Nuclear plant uses control rods to absorb excess neutrons that are released in a
fission reaction.
76.
Nuclear stability means that nucleus is stable meaning that it does
not spontaneously emit any kind of radioactivity.
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