ISP209 Spring Exam #3. Name: Student #:

Transcription

1 ISP209 Spring 2014 Exam #3 Name: Student #: Please write down your name and student # on both the exam and the scoring sheet. After you are finished with the exam, please place the scoring sheet inside the exam and turn in at the front of the lecture room. No section # or form ID is needed.. Do not begin working on the exam before permission is given. Keep your eyes on your own exam and no talking. Violation of this policy will result in a grade of 0 for the exam. No cell phones visible. Some useful constants: e = 1.6X10-19 C c= 3 X 10 8 m/s G=6.67X10-11 N.m 2 /kg 2 h= 6.63X10-34 J.S melectron=9.1x10-31 kg mproton=1.67x10-27 kg mneutron=1.67x10-27 kg MEarth=5.98X10 24 kg REarth=6.37X10 6 m MSun=2X10 30 kg RSun=6.96X10 8 m

2 Match each of the bosons with the force that it is responsible for a) W/Z b) photon c) gluon 1) Weak nuclear force a 2) Strong nuclear force c 3) Electromagnetic force b 4) A strong gravitational field a) speeds up a clock. b) slows down a clock. c) does not affect a clock. 5) According to the principle of equivalence a) observations made in an accelerating reference frame are indistinguishable from those made in a gravitational field b) space and time are two forms of the same thing c) mass and energy are two forms of the same thing d) electricity and magnetism are two forms of the same thing e) all of these 6) Calculate the de Broglie wavelength of an proton moving at one percent of the speed of light? a) 6.6X10-13 m b) 1.79x10-27 m c) 2.43X10-10 m d) 1.3X10-13 m e) 4.32X10-37 m λ = h p = 6.63X10 34 J.s (1.67X10 27 kg)(3x10 6 m / s) =1.33X10 13 m 7) In nuclear fission and fusion processes, the amount of mass converted to energy or otherforms is a) less than 1% b) about 10% c) about 20% d) about 30% e) 100% 8) The half- life of carbon 14 is 5730 years. If a 1- gram sample of old carbon is 1/8 as radioactive as 1- gram of a current sample, then the age of the old sample is about a) 716 years. b) 11,500 years. c) 17,200 years. d) 22,900 years. e) 46,000 years. 3 half- lives 9) Which experiment best demonstrates the particle- like nature of light? a) single- slit experiment b) double- slit experiment c) diffraction grating d) photoelectric effect e) none of the above 10) What is the escape velocity for a 500 kg mass at the equator of the Sun? a) 3X10 8 m/s b) 579 m/s c) 6.19X10 5 m/s d) 1.12X10 4 m/s e) 4.44X10 3 m/s v = 2GM R = 2(6.67X10 11 Nm 2 / kg 2 )(2X10 30 kg) 6.96X10 8 m v = 6.19X10 5 m / s

3 11) You are in a rocket traveling away from the sun at a speed of 0.95c. You measure the speed of the light coming from the sun towards you to be a) 0.05c b)0.95c c) depends on the frequency of the light d) 1.95c e) 1.0c 12) Compared to radio waves, the velocity of ultraviolet waves in a vacuum is a) more b) less c) the same 13) At what rate are photons emitted by a 50W lamp. Assume that all of the lamp s light has the same wavelength of 589 nm. a) 1.25X10 20 photons/s b) 1.5X10 20 photons/s c) 1.75X10 20 photons/s d) 2.0X10 20 photons/s e) 3.0X10 20 photons/s E = hc λ = (6.63X10 34 Js)(3X10 8 m / s) = 3.38X10 19 J 589X10 9 m 50J / s # photons / s = photons / s 3.38X10 19 J / photon =1.5X ) Energy released by the sun results from the process wherein atomic nuclei a) combine b) break apart c) both of these d) none of these 15) Which of the following photons has the greatest energy? a) ultraviolet light b) blue light c) green light d) red light e) infrared light 16) The more information one has about the energy of an electron, the less certain one is about a) the time it has that energy b) its position c) both of these d) neither of these 17) Uranium- 235, uranium- 238 and uranium- 239 are different a) elements. b) ions. c) isotopes. d) all of these 18) An alpha particle consists of a) a proton b) a neutron c) an electron d) a proton and a neurton e) two protons and two neutrons 19) A nucleon (constituent of a nucleus) is either a) a positron or an electron b) a proton or an electron c) a proton or a neutron d) a neutron or an electron e) a proton or a positron 20) A quark is a) an building block of hadrons b) a building block of nucleons c) an elementary particle d) all of these

4 21) Consider a spaceship that moves toward you at half the speed of light. It fires a probe toward you, relative to itself, at 0.8 the speed of light. Relative to you, the probe approaches at about a) 70% c. b) 87% c. c) 89% c. d) 93% c. e) 96% c. u + v 1+ uv c 2 = 0.5c + 0.8c 1+ (0.5c)(0.8c) = c 2 1.3c 1.4 = 0.93c 24) The reason that the wavelike nature of a moving baseball is not noticed in everyday life is that a) its composed of particles b) its frequency is too small c) its wavelength is too small d) it doesn t have a wavelike nature e) all of the above 22) According to the special theory of relativity, all laws of nature are the same in reference frames that a) accelerate. b) move in circles. c) move at constant velocity. d) oscillate. 23) A clock in a stationary reference frame has exactly one second between `ticks. When this clock is observed while moving at a speed of 0.95c, what is the time interval between ticks? a) 1 second b) 1.90 seconds c) 0.53 seconds d) 2.72 seconds e) 3.20 seconds γ = 1 1 v2 c 2 = = 3.20s 25) A quantum of light is called a(n) a) proton. b) neutron. c) electron. d) notron. 26) The Higgs mechanism a) explains the number of generations of quarks and leptons b) explains why gravity is so weak c) explains how particles acquire mass d) all of the above e) none of the above 27) When Lise Meitner received the letter from Otto Hahn, she realized that they had discovered evidence of a) Heisenberg s uncertainty principle b) nuclear fission c) nuclear fusion d) relativity e) Pauli exclusion principle

5 28) In the Bohr model of the atom, discrete radii and energy states result when an electron circles the atom in an integral number of a) de Broglie wavelengths b) frequencies c) diffraction patterns d) probability distributions e) electron masses 29) The most abundant element in the universe is a) hydrogen b) helium c) lead d) uranium e) americanium 30) Because of the apparent non- conservation of energy and momentum in beta decay, a new particle was postulated a) the neutron b) the neutrino c) the electron d) the proton e) the anti- proton 31) The idea of extra dimensions for the universe may explain why a) the weak force is so much weaker than any of the other forces b) the electromagnetic force is so much weaker than any of the other forces c) gravity is so much weaker than any of other forces d) why there are 3 families of quarks and leptons e) why there are 3 types of neutrinos 32) If the sun collapsed to a black hole, the time required for Earth to orbit the collapsed sun would a) increase. b) decrease. c) stay the same. 33) The half- life of a radioactive substance is INDEPENDENT of a) the number (if large enough) of atoms in the substance. b) whether the substance exists in an elementary state or in a compound. c) the temperature of the substance. d) the age of the substance. e) all of these 34) When Albert Einstein had the sudden insight during his walk with his friend in Bern (in the video shown in class), he realized that a) light was an electromagnetic wave b) light consisted of photons c) the concept of simultaneity of two events had to be abandoned d) Maxwell s equations had to be wrong e) the speed of light was constant 35) Which radiation has no electric charge associated with it? a) alpha rays b) beta rays c) gamma rays d) all of these 36) What process powers the Sun? a) chemical reactions b) gravitational interactions c) fission reactions d) fusion reactions e) dark energy interactions

6 37) Of the four fundamental forces, which have an infinite range of action (act over an infinite distance)? a) electromagnetic and gravitational b) strong and gravitational c) weak and electromagnetic d) weak and gravitational e) strong and weak 38) Most of the radioactivity we personally encounter comes from a) fallout from past and present testing of nuclear weapons. b) nuclear power plants. c) medical X rays. d) the natural environment. e) none of the above 39) Which of the following gives the correct ordering of the strengths of the four fundamental forces (from strongest to weakest)? a) strong, weak, electromagnetic, gravity b) strong, electromagnetic, gravity, weak c) strong, gravity, electromagnetic, weak d) gravity, strong, electromagnetic, weak e) strong, electromagnetic, weak, gravity 40) Cellphones can not cause cancer because a) the wavelengths of the microwaves are too short b) the intensity of the microwaves is too high c) the energy of the microwave photons is too low d) the frequency of the microwaves is too high e) cellphones don t emit any electromagnetic radiation