brodidit for students
Dawn of modern physics
Class 12 · Physics · 8 questions
Name: ____________________ Date: ____________
In the photoelectric effect, the maximum kinetic energy of emitted electrons depends on the:
- A Frequency of light
- B Area of metal
- C Time of exposure
- D Intensity of light
The energy of a photon is given by:
- A h f
- B h f²
- C h / f
- D f / h
de Broglie wavelength is:
- A p / h
- B h / p
- C h / E
- D h p
Compton scattering shows that light behaves as:
- A Particles
- B Only waves
- C Neutral rays
- D Sound
Einstein's famous mass energy relation is:
- A E = m c
- B E = m c²
- C E = m² c
- D E = c / m
The minimum frequency of light needed to emit photoelectrons is the:
- A Beat frequency
- B Threshold frequency
- C Resonant frequency
- D Critical frequency
Heisenberg's uncertainty principle says we cannot know exactly both the position and the:
- A Charge
- B Momentum
- C Colour
- D Mass
Pair production needs a photon of energy at least:
- A 13.6 eV
- B 1.02 MeV
- C 931 MeV
- D 0.51 MeV
Answer key
1. A, 2. A, 3. B, 4. A, 5. B, 6. B, 7. B, 8. B
KE max = h f - work function.
E = h f.
wavelength = h / momentum.
It treats a photon as a particle with momentum.
E = m c².
Below it no emission occurs.
The product of the uncertainties has a minimum.
It must supply the rest mass of an electron and a positron.