Modern Physics AFCAT Questions

AFCAT Physics

Modern Physics MCQ Questions


1.

What is the energy of a photon with frequency 5 × 1014 Hz?

A.

3.3 × 10-19 J

B.

5.0 × 10-19 J

C.

3.0 × 10-20 J

D.

2.5 × 10-18 J

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ANSWER :

A. 3.3 × 10-19 J

2.
Who proposed the quantum theory?
A.
Isaac Newton
B.
Max Planck
C.
Albert Einstein
D.
Niels Bohr
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ANSWER :
B. Max Planck
3.
In the photoelectric effect, electrons are ejected when:
A.
The light is intense
B.
The light is red
C.
The light’s frequency exceeds a threshold
D.
The metal is heated
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ANSWER :
C. The light’s frequency exceeds a threshold
4.
The rest mass of a photon is:
A.
Zero
B.
1 kg
C.
Infinite
D.
Depends on energy
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ANSWER :
A. Zero
5.
The unit of Planck’s constant is:
A.
Joule
B.
Joule-second
C.
Watt
D.
Watt-second
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ANSWER :
B. Joule-second
6.
According to Einstein’s mass-energy relation, energy is:
A.
Directly proportional to mass
B.
Inversely proportional to mass
C.
Independent of mass
D.
None of these
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ANSWER :
A. Directly proportional to mass