1. The units of Planck's constant h are joule-s, and the frequency of a light wave is f. The expression for the energy of a photon is (a) h / f(b) hf(c) f / h(d) none of the above

2. In an atom or solid, every electron is bound with some binding energy E b. If a photon is incident on this material, it can cause the emission of an electron. The maximum kinetic energy of this photoelectron is (a) hf(b) E b (c) hf + E b (d) hf - E b

3. In the photoelectron experiment on the right, the binding energy (work function) of an electron in the metal is E b. 1. How does the measured electron current change as the voltage V is increased in magnitude? (a) increases(b) decreases(c) stays the same 2. At what value of V does the measured electron current reach zero? (a) eV = hf - E b (b) eV = hf + E b (c) eV = hf(d) E b

4. The de Broglie wavelength relates a wave property (wavelength 8 ) with a particle property (momentum p). 1. Which of the following is the correct relationship? Hint: use dimensional analysis. The units of h are joule-s. (a) 8 = h/p (b) 8 = hp(c) 8 = p/h 2. What is the expression for the de Broglie wavelength of a particle of kinetic energy K? (a) 8 = p/K(b) 8 = K/h (c) (d) (e)

5. The square of the amplitude of a particle wave gives (a) the strength of the electric field at that point in space (b) the intensity of light at that point in space (c) the probability of finding the particle at that point in space (d) the distance to the particle from the origin

6. When an electron beam is incident upon the surface the incident electrons reflect back In a single crystal solid, all the atoms lie in a regular pattern, as shown below. (a) only in the direction with the angle of reflection equal to the angle of incidence (b) in all possible direction from the atoms (c) in those directions determined by interference of the individual electron waves from each atom.

7. When an electron beam is incident upon the surface the incident electrons reflect back and produces a pattern at the screen similar to that of In a single crystal solid, all the atoms lie in a regular pattern, as shown below. (a) Newton's rings (b) a sinusoidal wave (c) the pattern of a distant light as seen through a fine mesh.

8. When a guitar string is plucked, “standing waves” develop. The amplitude of the wave is zero at the two ends of the string, where it passes over a bar and so can’t vibrate. 1. Which of the following figures represents a possible wave for the string? The solid and dashed lines show the string's positions at its extremes. 2. Why? Why not?

9. 1. Which of the following represents an allowed wave for an electron in a circular orbit in the hydrogen atom? 2. Why? (a) Any wave is allowed whose wavelength is less than the circumference of the orbit. (b) The wave must be in phase with itself or there will be destructive interference which destroys the wave. (c) Because there is one proton in the nucleus, the wave experiences single-slit diffraction. (c) Neither. The wavelength must be longer than the circumference of the orbit. Electron wave

10. The solid curve in the left drawing below represents an allowed electron wave in a hydrogen atom. (c) Neither. The wavelength must be longer than the circumference of the orbit. Electron wave 1. Which of the following gives the radius r of an allowed electron orbit? (n = integer). (a) λ = 4πr (b) λ = πr 2 (c) n λ = 2πr (d) λ = 1/(n2πr) 2. Which of the following gives an allowed momentum p of an electron? (a) p =nh/(2πr) (b) p =h2πr (c) p =nh/r (d) p =h/(n2πr)

11. The figure on the right shows the allowed energy levels of the electron in a hydrogen atom. 1. What is the energy of the photon produced if the electron falls from the E 3 level to the E 1 level? (a) E 1 + E 3 (b) E 1 - E 3 (c) E 3 - E 1 (d) –E 1 – E 3 (e) E 3 / E 1 2. What is the numerical value of the photon energy? (a) 12.1 eV (b) -12.1 eV (c) 15.1 eV

12. Surface physicists can now create a straight row of metal atoms on an insulating surface. These rows act as 1-dimensional “wires”, sketched as the solid straight line below, in which an electron can move back and forth. Assume the electron's wave reflects in phase at the end of the wire. 1. Which of the following figures represents a possible wave for the electron? 2. Why?