Download Final Exam Review Worksheet

Final Exam Review
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Thermodynamics
8. Helium has the lowest boiling point of all the elements. It boils at -269 degrees Celcius. Convert this temperature to Kelvin.
9. How much heat must be given to 3.0 kg of water at 55 degrees Celcuis to convert it to 100.0 degree steam?
10. How much heat must be added to 250 grams of Methanol to raise the temperature 15 degrees Celcius?
11. How much heat must be given to 50.0 kg of ice at -54.0 deg. Celcius to convert it into steam at 1.20 x 102 degrees Celcius?
12. You pour 150.0 g of room temperature soda at 20.0 deg. Celcius into a 700.0 g frosted glass mug out of the freezer at -10.0 deg. Celcius. Ignoring the heat lost
to the surroundings, what temperature do they come to?
13. We all await Lake Beulah’s swimability in the summer. How many days does it take for Lake Beulah to go from 0 degree Celcius water to 60 degrees and
swimable? Lake Beulahs has approximately 93,580,000 gallons, assume that 6.00 x102 Watts of energy fall on it from the sun during ‘daylight (assume 10 hours
per day), assume that water has a density of 3.78 kg / gallon, and assume that all energy put into the lake stays there at night.
Essay ( 4 pts ) Answer each in complete sentences.
14. What does ‘specific heat’ mean? What is it?
15. Give an example of the three means of heat transfer.
Wave Properties
15. A piano string vibrates 262 times per second. What is the period of the wave?
16. If sound travels at 5600 m/s through a steel rod, what is the wavelength, given the wave has a frequency of 2480 Hz?
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17. What is the speed of a wave that has a frequency of 3.7  10 Hz and a wavelength of 1.2  10 cm?
18. The average distance from the earth to the moon is 384,790 km. If Earth’s atmosphere were uniform and extended to the moon’s surface, how many days
would it take for a sound to reach the moon? Assume the speed of sound is 343 m/s.
19. A surfer has 6 waves pass under him in 3 minutes. She guesstimates that there is approximately 100 m between each wave. What is the approximate speed
of the waves?
20. A hiker is standing 1000 m from a cliff. He hears his voice 10 seconds later. If the wavelength of his sound is .75 meters, what is the frequency of his voice?
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Short Answer.
22. Contrast the reflection of a wave that passes from one medium into a lighter, more flexible medium to a wave that passes from one medium into a heavier and
stiffer medium.
23. Devise an experiment to prove the concept of wave superposition.
Sound
21. A sound wave traveling at a speed of 340 m/s has a wavelength of 1.25 m. What is the frequency of the sound?
22. What is the wavelength and period of a sound made by a violin string vibrating at 640 Hz if the wave is traveling at 350 m/s.
23. What is the temperature of the air if the speed of sound is 351 m/s? Assume that the velocity of sound in air increases .6 m/s for each increase of 1 degree
Celcius. (Hint: use STP)
24. A tuning fork has a frequency of 365 Hz. In an air column, the fork causes the loudest sounds at resonant lengths that are separated by 45.6 cm. What is the
velocity of the sound? Recall that resonance lengths are spaced by half-wavelength intervals.
Short Answer
25. Explain how and why the apparent pitch of a train whistle is different for a person standing in front of a moving train, behind the moving train, and someone on
the moving train.
26. In space, no one can hear you scream. Why is that?
27. Your son / daughter one day ask you ‘What is sound? Where does it come from?’ What do you tell them?
28. How can one quickly estimate how far a thunderstorm is away (in miles) by watching the lightning?
Light
21. What is the frequency of light with a wavelength of 7.00 x 10-7 m? (1pt bonus: What is the color of that light?)
22. What is the illuminance for a piece of paper on a table 50 cm from a light source that is producing 1600 lm of luminous flux?
23. I’d like to put ground effects (UFO lighting) on my truck. The LED’s would be .5 m from the ground. What must the the luminous intensity of the bulbs be to
produce an illuminance of 22 lx?
24. A green laser produces a coherent light beam (meaning the peaks and valleys of the wave line up) with wavelengths equal to 510 nanometers. What is the
frequency of the wave? (in Megahertz, MHz)
25. A streetlight contains two identical bulbs 3.3 m above the ground. If the community wants to save electrical energy by removing one bulb, how far from the
ground should the streetlight be positioned to have the same illumination on the ground under the lamp?
Short Answer
25. How can one tell if light is polarized?
26. Contrast luminous flux and illuminance.
27. Describe the relationship between illumination on a surface and the distance the surface is from the light source.
Reflection & Refraction
15. A laser is shown into a block of leucite as shown below. Draw in all the beams that will emerge from such an angle. Label all angles and draw straight lines.
16. The speed of light in a clear plastic is 1.90 x 108 m/s. A ray of light strikes the plastic at an angle of 22 deg. At what angle is the ray refracted?
17. How many more minutes would it take light from the Sun (1.5 E 8 km away) to reach Earth if the space between them were filled with room temperature water
rather than a vacuum?
18. What is the speed of light through halite, commonly called rock salt. It’s index of refraction is 1.54.
19. What is the critical angle for halite immersed in room temp. water (n = 1.33)
20. A block of unknown material is submerged in room temperature water. Light in the water is incident on the block at an angle of 25 deg. The angle of refraction
in the block is 17 degrees. What is the critical angle of the unknown material if it were to be lifted out of the water into the air?
Short Answer.
21. Explain what total internal reflection is and how the critical angle relates to it.
Mirrors and Lenses
For 19 and 20, find the image with a ray diagram using a straight edge.
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Problems.
21. An object that is .95 cm tall and 4.2 cm from a convex lens produces a real image that is 2.8 cm from the other side of the lens. A) What is the size of the
image? B) What is the magnification of the lens? C) What is the focal length of the lens?
22. If a vehicle is 2.0 m high and 4.6 m from a car’s convex passenger rear view mirror. The radius of curvature for the mirror is 0.80 m. Find the A) position B)
size of the image. C) Is the image real or virtual?
23. You want to create a 0.035 m image of a flower that is 1.00 m high and 10.0 m from a concave mirror. What must the radius of curvature of the mirror be?
Short Answer
24. Contrast convex and concave lenses.
Current Electricity
16. What voltage has to be applied to Mr. Heer, who has a dry skin resistance of 234,000 Ω, such that he loses muscle control? Muscle control is lost with a
current of 15 mA.
17. The third generation ("dockable") iPods use a 3.7V, 630mAh lithium ion battery. The average current (depending greatly on volume and how often the screen
is lit) is 42 mA.
A) How many joules of energy does the battery deliver to the .mp3 player each second?
B) How much power (in Watts) does the .mp3 player use?
C) How much energy does the .mp3 player use to play for 2 hours? (Assume it is consuming the average current.)
18. A three-pack of 1.5 V hearing aid batteries costs $4.26. Each battery puts out 8.0 mA of current. Each battery lasts for 15 days. What is the cost per kilowatt
hour to operate the hearing aid with one battery?
19. A heating coil has a resitance of 7.0 Ω and operates on 120 V.
A) What is the current in the coil while it is operating?
B) How much energy is supplied to the coil in 45 minutes?
C) If the coil is immersed in an insulated container holding 10.0 kg of water, what will be the increase in the temperature
of the water? Assume that it is 75% efficient; that 75% of the energy applied goes into heating the water. The specific heat
of water is 4180 J/(kg∙°C).
Short Answer (5 points) Answer each question in a complete sentence.
20. Contrast Ammeters and Voltmeters in a circuit, specifically how they are attached to a circuit.
Series and Parallel
11. Two resistors of 3.0 Ω and 8.0 Ω are connected in series across a 9.0 V battery.
A) What is the total resistance of the circuit?
B) What is the current through the 3.0 Ω resistor?
C) What is the current through the 8.0 Ω resistor?
D) What is the voltage drop across each resistor?
12. A 15 Ω bell, an 8 Ω lamp, and a 12 Ω resistor are connected in parallel across a 42 V battery.
A) What is the total resistance of the circuit?
B) What is the current through each device?
C) What is the total current drawn by the circuit?
D) What is the voltage drop across each device?
13. Find the reading of each meter at the right.
14. Find the equivalence resistance of the circuit below. Assume all resistors are 50 Ω resistors. For full credit, show all work and simplification steps individually.
15. A power drill has a resistance of 8 Ω, when plugged into 120 V. The fuse is set to blow when 80 Amps are flowing through the circuit, because the wires in the
walls will begin to melt past then. How many drills must be plugged in (in parallel) for the fuse to blow? See the circuit below.