Q. If the mass of an object is 2 kg, what is its energy equivalent according to Einstein's equation E=mc^2? (2022)
-
A.
1.8 x 10^16 J
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B.
1.8 x 10^14 J
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C.
1.8 x 10^12 J
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D.
1.8 x 10^10 J
Solution
E = mc^2 = 2 kg * (3 x 10^8 m/s)^2 = 1.8 x 10^16 J.
Correct Answer:
A
— 1.8 x 10^16 J
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Q. If the wavelength of a light wave is doubled, what happens to its frequency? (2020)
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A.
Doubles
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B.
Halves
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C.
Remains the same
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D.
Quadruples
Solution
Frequency (f) is inversely proportional to wavelength (λ). If λ is doubled, f is halved.
Correct Answer:
B
— Halves
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Q. If the wavelength of a photon is doubled, what happens to its energy? (2019)
-
A.
It doubles
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B.
It halves
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C.
It remains the same
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D.
It quadruples
Solution
Energy is inversely proportional to wavelength (E = hc/λ). If λ is doubled, E is halved.
Correct Answer:
B
— It halves
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Q. In a hydrogen atom, what is the energy of the electron in the ground state? (Use Rydberg's constant R = 13.6 eV) (2023)
-
A.
-13.6 eV
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B.
0 eV
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C.
-1.51 eV
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D.
-3.4 eV
Solution
The energy of the electron in the ground state of hydrogen is -13.6 eV.
Correct Answer:
A
— -13.6 eV
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Q. What is the energy of a photon with a frequency of 5 x 10^14 Hz? (Planck's constant h = 6.626 x 10^-34 J·s) (2021)
-
A.
3.31 x 10^-19 J
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B.
1.32 x 10^-19 J
-
C.
2.48 x 10^-19 J
-
D.
4.97 x 10^-19 J
Solution
Energy (E) = h * frequency = 6.626 x 10^-34 J·s * 5 x 10^14 Hz = 3.31 x 10^-19 J.
Correct Answer:
A
— 3.31 x 10^-19 J
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Q. What is the main characteristic of a black body in terms of radiation? (2019)
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A.
Reflects all radiation
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B.
Absorbs all radiation
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C.
Transmits all radiation
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D.
Scatters all radiation
Solution
A black body absorbs all radiation incident on it, making it an ideal emitter of thermal radiation.
Correct Answer:
B
— Absorbs all radiation
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Q. What is the main concept of quantum mechanics that distinguishes it from classical mechanics? (2023)
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A.
Determinism
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B.
Wave-particle duality
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C.
Conservation of energy
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D.
Newton's laws
Solution
Wave-particle duality is a fundamental concept of quantum mechanics, indicating that particles exhibit both wave and particle properties.
Correct Answer:
B
— Wave-particle duality
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Q. What is the minimum energy required to remove an electron from a hydrogen atom in its ground state? (Ionization energy = 13.6 eV) (2023)
-
A.
1.6 x 10^-19 J
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B.
2.18 x 10^-18 J
-
C.
13.6 eV
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D.
3.2 x 10^-19 J
Solution
The minimum energy required to remove an electron from a hydrogen atom in its ground state is 13.6 eV.
Correct Answer:
C
— 13.6 eV
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Q. Which particle is responsible for carrying the electromagnetic force? (2019)
-
A.
Electron
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B.
Photon
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C.
Neutron
-
D.
Proton
Solution
The photon is the force carrier for electromagnetic interactions.
Correct Answer:
B
— Photon
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