Physics 586 - How Things Work II - Spring 2000
Final Examination

Time Limit 3 hours

Given Saturday, May 13, 1:30 p.m. Room 313 Physics Building
MULTIPLE CHOICE QUESTIONS

Please mark the best correct answer for each.

1. A uranium-238 nucleus undergoes fast fission during a nuclear explosion. If you were to collect all the fragments of that original uranium-238 nucleus, you would find that their total combined mass is
   1. about 0.1% more than that of the original uranium-238 nucleus.
   2. less than that of the original uranium-238 nucleus.
   3. exactly the same as that of the original uranium-238 nucleus.
   4. about 1.0% more than that of the original uranium-238 nucleus.
2. Compliments of Ms. Wyrick
   MacGyver, giving up his non-violent ways, decides to make a fission bomb to eliminate his enemies. Which of the following four conditions does NOT have to be satisfied in order for MacGyver do create an atomic or fission bomb?
   1. A source of neutrons has to exist in the bomb to trigger the explosion.
   2. The nuclei making up the bomb has to be "fissionable", that is they have to fission when hit by a neutron.
   3. Each induced fission has to produce the same number of neutrons that it consumed.
   4. The bomb has to use the released neutrons efficiently so that each fission induced an average of more than one subsequent fission.
3. Compliments of Ms. Wyrick
   Inspired by one of the Physics 106 video tapes, you decide to try one of the demos in your own classroom. Using a slide projector, you shine the beam of white light into a fish tank filled with water and a little bit of Carnation dry milk. The small milk molecules cause high frequency light to scatter. What color is the spot on the wall?
   1. blue
   2. white
   3. reddish orange
   4. black
4. Compliments of Mr. Kaufman
   My daughter knocks a round ceramic magnet off of the refrigerator door. When it hits the floor it cracks. What happens when I try to glue the two halves together.
   1. They don't stick together; the two halves repel each other.
   2. They stick together and the magnet is fixed, as long as you use crazy glue, not Elmer's glue.
   3. They don't stick together. Ceramic is a non-polar material, and glue only works on polar compounds.
   4. They stick together; the two halves attract each other.
5. Professor Bloomfield drew an analogy in nuclear physics by pulling a soap bubble apart until it broke in the middle. When it broke, what did you observe and what was the analogy?
   1. one tiny bubble - fission
   2. several tiny bubbles - fission
   3. several tiny bubbles - fusion
   4. one tiny bubble - fusion
6. A compact disc player or CD records the sound as an array of ridges and gaps. The height of the ridges on the CD are
   1. one quarter wavelength in height to achieve constructive interference between the light reflected from the gap and the ridge.
   2. one quarter wavelength in height to achieve destructive interference between the light reflected from the gap and the ridge.
   3. one half wavelength in height to achieve constructive interference between the light reflected from the gap and the ridge.
   4. one half wavelength in height to achieve destructive interference between the light reflected from the gap and the ridge.
7. An isotope of Uranium decays radioactively to lighter nuclei. That is, it spontaneously fissions. How was this nucleus formed in the first place? It was created by
   1. a supernova explosion of a dying star.
   2. the big bang explosion at the origin of the universe.
   3. a nuclear reactor.
   4. the huge amounts of pressure at the center of the earth.
8. Compliments of Ms. Traphagen
   When light travels through a medium (like water or a prism),
   1. its frequency increases and its wavelength stays the same.
   2. its frequency remains the same and its wavelength decreases.
   3. its frequency increases and its wavelength increases.
   4. its frequency decreases and its wavelength decreases.
9. Compliments of Ms. Traphagen
   In class we studied the nuclear activity present in stars, like our sun. Life on Earth would not be possible without energy from the sun. The sun, like a hydrogen bomb, generates energy by
   1. nuclear fission (splitting helium atoms into hydrogen).
   2. oxidation of hydrogen.
   3. fusing hydrogen into helium.
   4. radioactive decay which emits energized waves.
10. If you were to fabricate the most powerful explosion you could imagine, you would
    1. assemble a critical mass of uranium.
    2. assemble a critical mass of plutonium.
    3. assemble as much hydrogen as possible with a small amount of uranium.
    4. assemble about a megaton of TNT.
11. Compliments of Mr. Rezendes
    In the lecture on plastics, Dr. Bloomfield used an acne medicine called benzoyl peroxide. What was the purpose of the benzoyl peroxide?
    1. as an initiator of the polymerization reaction
    2. as a source of free radicals
    3. both a and b
    4. as a source of monomer
12. Professor Bloomfield showed examples of light totally internally reflected at various interfaces. In which case below would it not be possible to find an angle at which light is totally internally reflected?
    1. waterproof flashlight at the bottom of a swimming pool
    2. laser light in a fiber optic cable
    3. sunlight striking the surface of a calm lake between sunrise to sunset
    4. red light emitted from a laser diode placed inside a diamond
13. Compliments of Mr. Rezendes
    As the first person in the gym at night, I turn on the overhead lights. They come on dimly at first but brighten after a few minutes. Why?
    1. They are low-pressure bulbs and it takes a while for current flow to be a maximum.
    2. They are high-pressure bulbs and take a while to warm up.
    3. Some one must have recently turned them off and they take a while to restart.
    4. They are high voltage bulbs that need to come on slowly so that they do not trip a circuit breaker.
14. To slow down neutrons you would use materials such as heavy water, water, boron, and carbon. Water is better than carbon because
    1. more potential energy is taken up by the water molecule than the carbon atom for each collision with the neutron thereby reducing the energy of the neutron faster.
    2. more potential energy is taken up by the carbon atom than the water molecule for each collision with the neutron thereby reducing the energy of the neutron faster.
    3. more momentum is taken up by the hydrogen than carbon for each collision with the neutron thereby reducing the energy of the neutron faster.
    4. more momentum is taken up by the oxygen than carbon for each collision with the neutron thereby reducing the energy of the neutron faster.
15. To produce x-rays, electrons are accelerated in to a positive tungsten electrode at about 10% the speed of light. What is the most correct answer below?
    1. Bremsstrahlung x-rays are produced when the electron accelerates around the tungsten atom and characteristic x-rays are produced when the accelerated electron knocks out an orbiting atomic electron near the tungsten nucleus.
    2. Bremsstrahlung x-rays are produced when the electron accelerates around the tungsten atom and continuous x-rays are produced when the accelerated electron knocks out an orbiting atomic electron near the tungsten nucleus.
    3. Bremsstrahlung x-rays are produced when the electron accelerates around the tungsten nucleus and continuous x-rays are produced when the accelerated electron knocks out an orbiting atomic electron near the tungsten nucleus.
    4. Bremsstrahlung x-rays are produced when the electron accelerates around the tungsten nucleus and characteristic x-rays are produced when the accelerated electron knocks out an orbiting atomic electron near the tungsten nucleus.
16. Compliments of Mr. Kaufmann
    We said in class that computers (both fruit and PCs) represent all data digitally. This is done using the binary system, instead of the decimal system. How would a computer represent the number 21?
    1. 10101
    2. 10100
    3. 11011
    4. 11010
17. Compliments of Ms. Gray
    You have 4 pieces of wire made of the same material. One is short and thin, one is short and thick, one is long and thick and the other piece is long and thin. Which piece of wire will get the hottest if attached to a 6 V battery?
    1. the piece that is short and thin
    2. the piece that is short and thick
    3. the piece that is long and thick
    4. the piece that is long and thin.
18. X-rays are absorbed more by bones than by tissues because the heavier calcium in your bones absorbs more x-rays than the oxygen in your tissues due to what process?
    1. photo-electric process
    2. Bremsstrahlung process
    3. x-ray elastic scattering
    4. moderator
19. Compliments of Ms. Gray
    A store in Ocean City that sells "Super Cool Polarzoid Sunglasses". How can you determine if the sunglasses contain a polarizing filter or not?
    1. Place your finger near the outside of the lens and if there is a double image formed in the lens then the sunglasses contain a polarizing filter.
    2. Put on two pairs of glasses one size larger than the other and if more light shines through the two lenses than through a single lens they contain a polarizing filter.
    3. Take two pairs of sunglasses and hold the lenses close to each other but turn one 90 degrees to the other. If no light shines through the lenses they contain a polarizing filter.
    4. Take one pair of sunglasses near a bright light. If the glasses become darker then they contain a polarizing filter.
20. Compliments of Mr. Garrity
    Mrs. White's favorite radio station has an antenna connected to a large tank circuit. This tank circuit's main components are
    1. inductor and capacitor
    2. resistor and inductor
    3. resistor and capacitor
    4. inductor and diode
21. The fallout from a nuclear explosion and the waste from a nuclear reactor contain radioactive isotopes. For example, iodine-131 (a fission byproduct) is radioactive while iodine-127 (normal iodine) is not. An atom of iodine-131 differs from an atom of iodine-127 because the iodine-131 atoms has more
    1. protons in its nucleus.
    2. neutrons in its nucleus.
    3. electrons in its orbitals.
    4. gamma rays in its nucleus.
22. Compliments of Mr. Garrity
    Charge flows through a light bulb. Suppose a wire with no resistance is connected across the bulb as shown. When the wire is connected,
    
    1. all the charge continues to flow through the bulb.
    2. half the charge flows through the wire, the other continues through the bulb.
    3. all the charge flows through the wire.
    4. none of the above
23. In a compact CD player three lenses are used. One lens is used to create a parallel beam from the laser emitting diode and
    1. the second lens is used to focus the laser light on to the aluminum ridges on the CD and the third lens is used to focus light on to the sensor.
    2. the second lens is used to focus the laser light on to the aluminum ridges on the CD and the third lens is to correct for diffraction effects of the light emitting diode.
    3. the second lens is used to focus the laser light on to the aluminum ridges on the CD and the third lens is used create another parallel beam of light incident on the sensor.
    4. the second lens is used to create another parallel beam of light incident on the aluminum ridges on the CD and the third lens is used to focus light on to the sensor.
24. Light travels at 186,400 miles per second in a vacuum and roughly the same speed in air. Suppose you are traveling with a flash light in a levitated train traveling at half the speed of the light 93,200 miles per sec and the flashlight is pointed in the same direction as the train is moving. A hobo standing by the tracks watching the train go by thinks the speed of light from the flashlight in the moving train is
    1. 186,400 miles per sec
    2. 279,600 miles per sec
    3. 130,800 miles per sec
    4. 93,200 miles per sec
25. Professor Bloomfield made a plot of the energy per nucleon per nucleus. The amount of energy stored in a nucleus per nucleon is
    1. maximum in the lightest nuclei and a minimum near iron nuclei.
    2. maximum in the heaviest nuclei and a minimum near the iron nuclei.
    3. minimum in the heaviest nuclei and a maximum near the iron nuclei.
    4. minimum in the heaviest nuclei and a maximum in the lightest nuclei.
26. When an x-ray photon is absorbed in a tumor, it may cause the tumor cell to die because the photon
    1. causes the cell to crystallize into a brittle solid that cannot tolerate any deformation.
    2. carries enough energy to damage molecules and cause chemical injury to the cell.
    3. magnetizes the cell and causes it to stick to passing killer cells of the immune system.
    4. polarizes the cell and causes its vertical electric field to become horizontal.
27. Compliments of Mr. Garrity
    While replacing an ordinary light bulb, Patrick cracks the glass covering, but not the filament. When the bulb is screwed in and turned on, it will most likely
    1. light up and work as normal.
    2. light up then burn out quickly.
    3. light up then burn less brightly.
    4. not light up at all.
28. Compliments of Ms. Hamlin
    The cathode-ray tube in a color television is different from a black and white television set in that
    1. the screen is coated with many different colors in a color television.
    2. the screen is red, blue, and green in a color television.
    3. only one electron gun is necessary in a color television.
    4. there are three electron guns in a cathode-ray tube in a color television.
29. Compliments of Ms. Hamlin
    Which one of the following statements is correct about nuclear isotopes?
    1. They all have the same binding energy.
    2. They all have the same mass number.
    3. They all have the same number of nucleons.
    4. They all have the same number of protons.
30. Put the following polymers, trash bags, silly putty, silicon lubricants, plexiglas, and latex house paint in the proper regimes:
    1. glassy , liquid flow, glass rubber transition, rubbery plateau, and rubbery flow
    2. glassy , rubbery plateau, rubbery flow, glass rubber transition, and liquid flow
    3. rubbery plateau ,glassy , glass rubber transition, rubbery flow, and liquid flow
    4. rubbery plateau, rubbery flow, liquid flow, glassy, and glass rubber transition
31. A process to make a polymer stiff, but elastic at any temperature, was named after the Roman God of fire. This process was invented by
    1. American Chemist Wallace Hume Carothers and Julian Hill.
    2. American Physicist Steven Chu.
    3. American Inventor Charles Goodyear.
    4. German Chemist and Nobel Prize winner Hermann Staudinger.
32. Cellulose is a polymer built from sugar molecules found naturally in trees and plants. Most animals such as cows can not digest cellulose, because they can not break the molecular chains to release the sugar molecules, yet these animals still eat the plants. This is because
    1. the bacteria in the stomachs of the cows convert the cellulose into sugar molecules for the cow.
    2. the acid in the stomach of the cow dissolves the cellulose into sugar.
    3. the cows pass the cellulose through their systems without the benefit of the sugar.
    4. the stomach temperature of the cow due to the bacteria in the stomach converts the cellulose into a different regime allowing it to become digestible.
33. Propane, diesel fuel, paraffin wax, polyethylene, and teflon consist of chain-like molecules that are roughly: 3, 16, 30, 1000-3000, and 100,000 atoms long, respectively. Teflon or polytetrafluoroethylene consists of chains of carbon atoms surrounded by another atom making it one of the most chemically inert materials in existence. Rubbing it with silk on the other hand produces lots of electrical charge - more so than any other material. This other atom is:
    1. Hydrogen
    2. Oxygen
    3. Chlorine
    4. Fluorine
34. Magnetic resonance imaging or MRI takes advantage of the quantum nature of the spin of the
    1. electron in a hydrogen atom.
    2. proton in a hydrogen atom.
    3. proton in an oxygen nucleus.
    4. electron in an oxygen atom.
35. The four fundamental forces in nature are the gravitational, electromagnetic, strong and weak forces. For the question below neglect the weak force. When two automobiles collide head on travelling at 50 mile per hour, what are the fundamental forces that actually determine the outcome of the collision?
    1. gravitational and strong
    2. electromagnetic and gravitational
    3. electromagnetic
    4. none of the above
36. Aluminum foil blocks visible light, but is mostly transparent to high energy x-rays. What is the simple explanation for this phenomenon?
    1. Aluminum atoms scatter the longer wavelength light and do not scatter the shorter wavelength x-rays because they squeeze right through the space between the atomic electrons.
    2. Aluminum atoms scatter the longer wavelength light and do not scatter the shorter wavelength x-rays because they squeeze right through the space between the atoms but not the atomic electrons.
    3. Aluminum atoms scatter the longer wavelength light and do not scatter the longer wavelength x-rays because they are larger than the diameter of the aluminum atoms.
    4. Both A and B
37. Making x-rays for medical use to treat patients is accomplished by accelerating electrons through 100,000 volts into a rotating tungsten anode. X-ray photons leaving the anode can carry energy up to 100,000 electron volts of energy. A filter is added to stop the lower energy x-rays and pass the higher energy x-rays because
    1. the lower energy x-rays are not useful for imaging or therapy.
    2. the lower energy x-rays heat the skin.
    3. the lower energy x-rays can scatter around the room making it difficult to shield the patient from them.
    4. both A and B
38. Deep seated tumors in the body can not be reached by most x-rays. Here very energetic x-rays called gamma rays are used. These gamma rays have more than a million electron volts of energy. The deep seated tumor is killed when energy is deposited at the tumor site through the quantum processes in the following order of importance:
    1. Compton scattering, Photo-electric effect, Electron-positron pair production
    2. Compton scattering, Electron-positron pair production, Photo-electric effect
    3. Photo-electric effect, Compton scattering, Electron-positron pair production
    4. Photo-electric effect, Compton scattering, Photo-electric effect
39. Fissile material such as uranium 235 is used as fuel in a nuclear reactor and to make nuclear bombs. Nuclear reactors may pose a threat to our radiation safety, but are not a threat to explode like a nuclear bomb. This is because
    1. the fissionable material in a nuclear reactor is close to critical mass and spread out over the core.
    2. the fissionable material in a nuclear reactor is well below critical mass and spread out over the core.
    3. the fissionable material in a nuclear reactor is well above critical mass and spread out over the core.
    4. the fissionable material in a nuclear reactor is well below critical mass and concentrated in the core.
40. In a pressurized water reactor which uses Uranium 235, energy is extracted from the nuclear fissions by
    1. heating up water which acts as a moderator and coolant to the reactor core.
    2. heating up water which acts only as a coolant to the core.
    3. heating up liquid sodium which acts as a coolant.
    4. heating up water until it boils in the reactor core and extracting the steam to turn an electric generator.
41. Compliments of Mr. Kaufmann
    Which of the following was created in class by mixing Methyl methacrylate with Benzoic peroxide?
    1. Kevlar
    2. High Density Polyethylene
    3. Plexiglas
    4. Teflon
42. Compliments of Mr. Harnsburger
    Stephanie has connected the primary circuit (10 coils) of a small toy transformer up to a direct current from her Dad's old but working 6 volt car battery. The secondary circuit (20 coils) of the transformer is connected to a 12 volt light bulb. What is the most likely observation by Stephanie?
    1. The transformer gets hot, the prinary burns up, and the bulb does not light up.
    2. The bulb lights up and then the filament breaks and the light goes out.
    3. The transformer gets hot, but the bulb lights up.
    4. The bulb lights up normally.
43. Compliments of Mr. Harnsburger
    As light passes from the air into a window pane of glass
    1. the speed of light decreases and bends away from the normal.
    2. the speed of light decreases and bends towards the normal.
    3. the speed of light remains the same and bends toward the normal.
    4. the speed of light remains the same and bends away from the normal
44. Compliments of Mr. Kaufmann
    The image formed by the lens is described as real and inverted. If the object is moved to inside the focal length, the image formed is described as
    
    1. real and inverted.
    2. virtual and inverted.
    3. virtual and erect.
    4. real and erect.
45. Compliments of Mr. Kaufmann
    Which statement best describes the difference between a beam of light from a laser and one from a focused penlight?
    1. the laser light is red and the penlight is white.
    2. the laser light is composed of coherent photons of one wavelength and the penlight is composed of incoherent photons of one wavelength.
    3. the laser light is composed of coherent photons of one wavelength and the penlight is composed of photons of coherent light of many wavelengths.
    4. the laser light is composed of coherent photons of one wavelength and the penlight is composed of photons of incoherent light of many wavelengths.
46. Compliments of Ms. Traphagen
    How does Sarah's rear-view car mirror work during both daytime and nighttime driving?
    1. In day the light reflects off the back of the reflecting mirror and at night she tilts it so the light is reflected off the surface of the glass.
    2. In day the light reflects off the front of the mirror surface, at night it reflects off the back of the mirror surface.
    3. When she flips the day mirror to night mirror, the index of refraction changes which alters the amount of light reflected back to her eyes.
    4. By flipping the angle of the mirror she changes the angle of incidence, which causes less light to hit her eyes at night.
47. Compliments of Ms Traphagen
    We had a debate in class about the state of matter for glass (liquid or solid?). The final resolution was that glass is a solid because
    1. although it is amorphous, like a liquid, it responds to shear stress with shear strain.
    2. it is able to permanently maintain its own shape.
    3. it has a microscopically crystalline structure.
    4. it is not amorphous and does not respond to shear stress (it only responds to tensile stress).
48. A piece of calcite has two indices of refraction, a value of 1.70 for vertically polarized light and a value of 1.52 for horizontally polarized light. This crystal is used as a beam splitter in a compact disc to deliver one beam of laser light towards the compact disk surface and another beam
    1. towards the sensing photodiodes.
    2. is not used.
    3. is refurbished and sent back in again.
    4. is used as a monitor to prevent gain shifts.
49. Safety glasses and bullet proof glass are made by
    1. adding lead to glass which makes it harder and increases its index of refraction.
    2. tempering glass by heating it until it softens and then cooling it suddenly with blast of cold air.
    3. laminating sheets of plastic between annealed glass so that a single crack in one sheet does not propagate through to the next sheet.
    4. bathing the soda-lime-silica glass in a potassium liquid so that the large potassium ions replace the sodium ions.
50. When a sharp knife is pushed down through a hard carrot placed on a cutting board, the vertical forces all cancel out so how can you cut through the carrot?
    1. The knife edge is so sharp it wiggles its way through the atoms.
    2. The normal force pushes up and forces the carrot through the knife.
    3. The electromagnetic forces near the tip of the blade are so strong that they break the atomic bonds between the carrot molecules.
    4. The horizontal forces produced by the wedge shape nature of the blade separate the carrot by braking the fibers down.