Photoelectric Effect MCQs with Numerical Problems
Photoelectric Effect MCQs with Numerical Problems
Class: CBSE Class 12
Subject: Physics
Section: Dual Nature of Radiation & Matter
Topic: Photoelectric Effect
Based on: CBSE Board Examination Pattern (NCERT)
Instructions: These Multiple Choice Questions (MCQs) are designed strictly as per the NCERT syllabus, making them ideal for CBSE Class 12 Board Examination preparation.
1. Photoelectric emission occurs when light frequency is:
Answer: C
Emission occurs only if ν ≥ ν₀ (threshold frequency).
Emission occurs only if ν ≥ ν₀ (threshold frequency).
2. Einstein photoelectric equation is:
Answer: A
Photon energy equals work function + maximum kinetic energy.
Photon energy equals work function + maximum kinetic energy.
3. If frequency increases, KE of electrons:
Answer: B
KEmax = hν − φ.
KEmax = hν − φ.
4. Work function unit is:
Answer: A
It represents minimum energy to eject electron.
It represents minimum energy to eject electron.
5. Stopping potential is used to find:
Answer: B
eV₀ = KEmax.
eV₀ = KEmax.
6. If ν = 2ν₀, KEmax will be:
Answer: B
KE = h(2ν₀ − ν₀) = hν₀.
KE = h(2ν₀ − ν₀) = hν₀.
7. Threshold wavelength formula:
Answer: A
λ₀ = hc/φ.
λ₀ = hc/φ.
8. If intensity doubles, photocurrent:
Answer: B
More photons → more electrons.
More photons → more electrons.
9. Photon momentum is:
Answer: A
p = h/λ.
p = h/λ.
10. If stopping potential = 3 V, KEmax =
Answer: A
KEmax = eV₀ = 3 eV.
KEmax = eV₀ = 3 eV.
11. Photoelectric effect proves light is quantised.
Answer: A
Energy is transferred in photons.
Energy is transferred in photons.
12. No emission occurs if:
Answer: A
Frequency must exceed threshold.
Frequency must exceed threshold.
13. KEmax depends on:
Answer: B
Higher frequency → higher KE.
Higher frequency → higher KE.
14. Photocurrent depends on:
Answer: A
More photons → more electrons.
More photons → more electrons.
15. Work function is property of:
Answer: B
Depends on material surface.
Depends on material surface.
16. Emission is instantaneous due to:
Answer: B
Energy transfer is immediate.
Energy transfer is immediate.
17. Increasing intensity does not change:
Answer: A
KE depends only on frequency.
KE depends only on frequency.
18. Threshold frequency depends on:
Answer: A
Material property.
Material property.
19. If λ increases, photon energy:
Answer: B
E = hc/λ.
E = hc/λ.
20. Device based on photoelectric effect:
Answer: A
Photocells convert light to electrical signal.
Photocells convert light to electrical signal.
