Quiz Chapter 7: Quantum Physics

1. Calculate the energy of a single photon of blue light with a frequency of 6.0 × 10¹⁴ Hz. (Planck's constant h = 6.63 × 10⁻³⁴ J s)

1. 3.98 × 10⁻¹⁹ J
2. 1.11 × 10⁻⁴⁷ J
3. 3.98 × 10⁻²⁷ J
4. 1.80 × 10⁻¹⁹ J

2. Why could classical wave theory NOT explain the photoelectric effect?

1. Classical theory predicted that electron emission required continuous light wave energy buildup over time
2. Classical theory predicted that light travels faster in dense media
3. Classical theory predicted that electrons carry positive charges
4. Classical theory stated that photons have zero momentum

3. In a photoelectric experiment, the stopping potential V_s is measured to be 1.5 V. What is the maximum kinetic energy of the photoelectrons in Joules? (e = 1.6 × 10⁻¹⁹ C)

1. 2.4 × 10⁻¹⁹ J
2. 1.07 × 10⁻¹⁹ J
3. 1.50 J
4. 3.84 × 10⁻¹⁹ J

4. What is the threshold frequency (f₀) of a metal?

1. The maximum frequency of light that causes reflection
2. The minimum frequency of light required to emit photoelectrons from a metal surface
3. The frequency at which photoelectrons reach zero kinetic energy in a vacuum
4. The frequency of light produced by thermal heating

5. A solar panel in a satellite converts light energy directly into electrical energy using the:

1. Thermionic emission process
2. Photoelectric effect
3. Electromagnetic induction process
4. Nuclear fusion process

6. Light of photon energy 5.0 × 10⁻¹⁹ J strikes a metal surface with a work function of 3.2 × 10⁻¹⁹ J. What is the maximum kinetic energy of the emitted photoelectrons?

1. 8.2 × 10⁻¹⁹ J
2. 1.8 × 10⁻¹⁹ J
3. 1.56 × 10⁻¹⁹ J
4. 3.2 × 10⁻¹⁹ J

7. What happens to the stopping potential (V_s) if light of a higher frequency is used in a photoelectric setup?

1. Stopping potential decreases
2. Stopping potential increases
3. Stopping potential remains unchanged
4. Stopping potential drops to zero

8. If the stopping potential for photoelectrons emitted from a metal plate is 2.0 V, what is the maximum velocity of the photoelectrons? (m_e = 9.1 × 10⁻³¹ kg, e = 1.6 × 10⁻¹⁹ C)

1. 8.39 × 10⁵ m s⁻¹
2. 7.04 × 10¹¹ m s⁻¹
3. 3.51 × 10⁵ m s⁻¹
4. 1.20 × 10⁶ m s⁻¹

9. If light of frequency f below the threshold frequency (f < f₀) shines on a metal surface, what happens?

1. Photoelectrons are emitted very slowly after a long time delay
2. No photoelectrons are emitted regardless of light intensity
3. Photoelectrons are emitted with maximum kinetic energy
4. The metal surface instantly melts

10. What is the gradient of a K_max against frequency (f) graph for any photoelectric metal surface?

1. Work function (Φ)
2. Planck's constant (h)
3. Threshold frequency (f₀)
4. Electron mass (m_e)