5.At what speed is a particle traveling if its kinetic energy is three times its rest energy? A) 0.879c B) 0.918c C) 0.943c D) 0.

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1 1.Two identical light waves, A and B, are emitted from different sources and meet at a point P. The distance from the source of A to the point P is L A ; and the source of B is a distance L B from P. Which one of the following statements is necessarily true concerning the interference of the two waves? A) A and B will interfere constructively because their amplitudes are the same. B) A and B will interfere constructively if L A = L B. C) A and B will interfere destructively if L A L B = mλ where m = 0, 1, 2, 3,... D) A and B will interfere destructively if L A is not equal to L B. 2.A double slit is illuminated with monochromatic light of wavelength nm. The m = 0 and m = 1 bright fringes are separated by 1.8 cm on a screen which is located 3.5 m from the slits. What is the separation between the slits? A) m B) m C) m D) m 3.A bomb is designed to explode 2.00 s after it is armed. The bomb is launched from earth and accelerated to an unknown final speed. After reaching its final speed, however, the bomb is observed by people on earth to explode 2.90 s after it is armed. What is the final speed of the bomb just before it explodes? A) 0.492c B) 0.524c C) 0.611c D) 0.882c 4.An alien spacecraft flies directly over a football stadium at a speed of 0.50c. If the proper length of the field is 100 yards, what field length is measured by the crew of the alien spacecraft? A) 59 yards B) 75 yards C) 87 yards D) 113 yards Page 1 5.At what speed is a particle traveling if its kinetic energy is three times its rest energy? A) 0.879c B) 0.918c C) 0.943c D) 0.968c

2 6.How much work (in joules) would have to be done to stop a 2-kg object moving at 0.90 c? A) 2.33 x B) 3.78 x C) 5.71 x D) 2.57 x Which one of the following statements concerning the proper time interval between two events is true? A) The proper time interval is the longest time interval that any inertial observer can measure for the event. B) The proper time interval is the shortest time interval that any inertial observer can measure for the event. C) The proper time interval is the time measured by an observer who is in motion with respect to the event. D) The proper time interval depends upon the speed of the observer. 8.Determine the de Broglie wavelength of a neutron (m = kg) that has a speed of 5.0 m/s. A) 79 nm B) 162 nm C) 395 nm D) 529 nm 9.Electrons are emitted from a certain metal with a maximum kinetic energy of 2 ev when 6-eV photons are incident on its surface. If photons of twice the wavelength are incident on this metal which one of the following statements is true? A) No electrons will be emitted. B) Electrons will be emitted with a maximum kinetic energy of 3 ev. C) Electrons will be emitted with a maximum kinetic energy of 6 ev. D) Electrons will be emitted with a maximum kinetic energy of 1 ev.. 10.The x component of the velocity of an electron (m = kg) is known to be between 100 m/s and 300 m/s. Which one of the following is a true statement concerning Page 2

3 the uncertainty in the x coordinate of the electron? A) The maximum uncertainty is about 10 6 m. B) The minimum uncertainty is about m. C) The maximum uncertainty is about m. D) The minimum uncertainty is about m. 11.When ultraviolet photons with a wavelength of m are directed at the surface of an unknown metal in vacuum, electrons with a maximum kinetic energy of 1.52 ev are emitted from the surface. What is the work function of the metal? A) 3.60 ev B) 3.11 ev C) 2.59 ev D) 2.08 ev 12.Which one of the following statements is the assumption that Niels Bohr made about the angular momentum of the electron in the hydrogen atom? A) The angular momentum of the electron is zero. B) The angular momentum can have only certain discrete values. C) Angular momentum is not quantized. D) The angular momentum can have any value greater than zero because it's proportional to the radius of the orbit. 13.The electron in a hydrogen atom is in the n = 3 state. What is(are) the possible value(s) for an emitted photon? A) 1.89 ev or ev B) 1.89 ev or 13.6 ev C) 0.66 ev or 13.6 ev D) 0.66 ev or ev 14.An electron is in the ground state of a hydrogen atom. A photon is absorbed by the atom and the electron is excited to the n = 2 state. What is the energy in ev of the photon? A) 13.6 ev B) 10.2 ev C) 3.40 ev D) 1.51 ev Page 3

4 15.Approximately what is the wavelength (in nm) of light that is emitted when an electron in hydrogen de-excites from the n = 3 level to the n = 1 level? A) 100 B) 140 C) 160 D) A light ray is traveling in a diamond (n = 2.419). If the ray approaches the diamond-air interface, what is the minimum angle of incidence that will result in all of the light reflected back into the diamond? The index of refraction for air is A) B) C) D) An object is placed 6.5 cm from a thin converging lens with a focal length of 14 cm. Which one of the following statements is true concerning the image? A) The image is virtual and 6.0 cm from the lens. B) The image is virtual and 12 cm from the lens. C) The image is real and 3.0 cm from the lens. D) The image is real and 6.0 cm from the lens. 18.A converging lens with a focal length of 12 cm produces a 3-cm high virtual image of a 1-cm high object. Which entry in the table below is correct? image distance location of image A) 8 cm same side of lens as object B) 8 cm opposite side of lens from obje C) 12 cm opposite side of lens from obje D) 24 cm same side of lens as object Use the following to answer question 19: A diverging lens has a focal length of 15 cm. A 5-cm object is placed 35 cm from the lens. 19.What is the magnification of the image? Page 4

5 A) +0.3 B) 0.3 C) +0.7 D) Mrs. Kim has been prescribed contact lenses that have a +3.2-diopter refractive power. With the contact lenses, she can read a magazine held 25 cm from her eyes. Which one of the following statements is necessarily true? A) She has a far point of 3.22 m. B) She has a far point of 0.25 m. C) She has a near point of 1.66 m D) She has a near point of 0.80 m. Page 5

6 Answer Key 1.B 2.C 3.D 4.C 5.D 6.A 7.B 8.A 9.D 10.C 11.D 12.B 13.A 14.B 15.A 16.A 17.B 18.D 19.A 20.D Page 6

A) n L < 1.0 B) n L > 1.1 C) n L > 1.3 D) n L < 1.1 E) n L < 1.3

A) n L < 1.0 B) n L > 1.1 C) n L > 1.3 D) n L < 1.1 E) n L < 1.3 1. A beam of light passes from air into water. Which is necessarily true? A) The frequency is unchanged and the wavelength increases. B) The frequency is unchanged and the wavelength decreases. C) The