Photoelectric Effect NEET Questions

Physics - Dual Nature of Matter and Radiation

Photoelectric Effect MCQ Questions


13.
If the intensity of light is increased keeping frequency constant (above threshold), the saturation current:
A.
Increases proportionally
B.
Remains the same
C.
Decreases proportionally
D.
First increases then decreases
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ANSWER :
A. Increases proportionally
14.
The minimum negative potential applied to the anode for which photocurrent becomes zero is called:
A.
Threshold potential
B.
Stopping potential (cut-off potential)
C.
Critical potential
D.
Saturation potential
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ANSWER :
B. Stopping potential (cut-off potential)
15.
For a fixed frequency of incident light, the stopping potential is:
A.
Proportional to square of intensity
B.
Inversely proportional to intensity
C.
Independent of intensity
D.
Directly proportional to intensity
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ANSWER :
C. Independent of intensity
16.
The maximum kinetic energy of photoelectrons is related to the stopping potential by:
A.
Kₘₐₓ = e²V₀
B.
Kₘₐₓ = (1/2)eV₀
C.
Kₘₐₓ = V₀/e
D.
Kₘₐₓ = eV₀
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ANSWER :
D. Kₘₐₓ = eV₀
17.
Below the threshold frequency, photoelectric emission:
A.
Occurs only after a long delay
B.
Does not occur regardless of intensity
C.
Occurs only at very high intensities
D.
Occurs but with negligible current
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ANSWER :
B. Does not occur regardless of intensity
18.
The time lag between incidence of light and emission of photoelectrons is approximately:
A.
A few seconds
B.
Less than 10⁻⁹ second (essentially instantaneous)
C.
About 1 hour at low intensity
D.
Several minutes
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ANSWER :
B. Less than 10⁻⁹ second (essentially instantaneous)