31.1

31.2

31.3 Photoelectric Effect

31.4 Photoelectric Effect

31.5 Light as Particles

31.6 Light as Waves Light as Particles & Waves 2-slit experiment

31.7 Electrons as Particles & Waves

31.8 Electrons as Particles & Waves

31.9

Questions -- MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.

) Quantum uncertainties are most predominant for simultaneously measuring the speed and location of A)an electron. B)a spitball. C) a baseball. 2) Two beams of light, a red beam and a blue beam, have the same energy. The beam with the greater number of photons is the A)blue beam. B)red beam. C) both the same.

) Which has more energy per photon? A) red light B) blue light C) Both have the same energy. 4) Two photons have the same wavelength. They also have the same A)energy. B) frequency. C) both of these. D) neither of these.

) In the photoelectric effect, the greater the frequency of the illuminating light, the greater the A)number of ejected electrons. B) maximum velocity of ejected electrons. C) both of these. D) neither of these. 6) A radiation detector measures the radioactivity of a piece of radium by catching and counting alpha particles it emits. According to quantum physics, making this measurement affects the A)radiation rate of the piece of radium. B) alpha particles that are caught. C) both of these. D) neither of these.

) In the equation E = hf, the f stands for A) wave frequency as defined for sound, radio, and light waves. B) frequency characteristic of quantum phenomena. C) the smaller wavelengths of visible light. D) none of these. 8) The ratio of a photon's energy to its frequency is A) Planck's constant. B) its amplitude. C) its wavelength. D) its speed. E) none of these.

) According to the uncertainty principle, the more we know about a particle's momentum, the less we know about its A) speed. B) location. C) kinetic energy. D) mass E) none of these. 10) Which of the following has the longer wavelength? A) a high-energy electron B) a low-energy electron C) Both have the same wavelength.

) According to quantum physics, looking at a star through a telescope A) has no effect on the processes occurring in the star. B) affects the processes occurring in the star. 12) Light behaves primarily as a wave when it A)interacts with matter. B) travels from one place to another.

) The ratio of the energy of a photon to its frequency is A) Planck's constant. B) pi. C) the photon's speed. D) the photon's wavelength. E) not known. 14) An electron and a baseball move at the same speed. Which has the longer wavelength? A) the electron B) the baseball C) Both have the same wavelength.

) In the double-slit experiment with electrons, the electrons arrive at the screen in a A) particle-like way with a pattern that is wave-like. B) particle-like way with a pattern that is particle-like. C) wave-like way with a pattern that is particle-like. D) wave-like way with a pattern that is wave-like. 16) In the photoelectric effect, the brighter the illuminating light on a photosensitive surface, the greater the A)number of ejected electrons. B) velocity of ejected electrons. C) both of these. D) neither of these.

Answers -- MULTIPLE CHOICE. The one alternative that best completes the statement or answers the question.

31.20 Chapter 31 1) Answer: A 2) Answer: B 3) Answer: B 4) Answer: C 5) Answer: B 6) Answer: B 7) Answer: A 8) Answer: A 9) Answer: B 10) Answer: B 11) Answer: A 12) Answer: B 13) Answer: A 14) Answer: A 15) Answer: A 16) Answer: A