General Science - Physics MCQs
Physics Objective (Multiple Choice) General Knowledge & General Science Questions & Answers for SSC-CGL, UPPSC, UPSC, NDA, CDS and UPSC Civil Services Prelims Examinations.
41. Which of the following is true about a cyclic process?
[A] the total heat absorbed equals the work done by the system.
[B] the system returns to its initial state
[C] Both a and b
[D] None
Show Answer
Correct Answer: C [Both a and b]
Notes:
In a cyclic process, the system returns to its initial state and the total heat absorbed equals the work done by the system.
42. What is the eye defect when a person can see nearby objects clearly but cannot see distant objects distinctly known as?
[A] Cataract
[B] Myopia
[C] Hypermetropia
[D] Presbyopia
Show Answer
Correct Answer: B [Myopia]
Notes:
Myopia is also known as near-sightedness. A person with myopia can see nearby objects clearly but cannot see distant objects distinctly.
43. How can a moving coil galvanometer be converted into a voltmeter?
[A] by introducing shunt resistance in parallel
[B] by introducing shunt resistance in series
[C] by introducing large resistance in series
[D] None of the above
Show Answer
Correct Answer: C [by introducing large resistance in series]
Notes:
A moving coil galvanometer can be converted into a voltmeter by introducing a resistance of a large value in series.
44. Which of the following is correct?
[A] Soft iron is a hard ferromagnetic material
[B] Alnico is a soft ferromagnetic material
[C] At high enough temperature, a ferromagnet becomes a paramagnet
[D] All of the above
Show Answer
Correct Answer: C [At high enough temperature, a ferromagnet becomes a paramagnet]
Notes:
The ferromagnetic property depends on temperature. At high enough temperature, a ferromagnet becomes a paramagnet. Soft iron is a soft ferromagnetic material and Alnico is a hard ferromagnetic material.
45. Which of the following is the name given to electrons moving at high speed?
[A] Alpha particles
[B] Beta particles
[C] Gamma particles
[D] None
Show Answer
Correct Answer: B [Beta particles]
Notes:
Beta particles are the electrons moving at high speed.
46. What is the energy equivalence of one atomic mass unit?
[A] 93.125 eV
[B] 931.25 eV
[C] 9.31 eV
[D] 0.93125 eV
Show Answer
Correct Answer: B [931.25 eV]
Notes:
1 a.m.u. represents the average mass of a nucleon and 1 a.m.u. = 931.25 eV.
47. What is meant by Atomic number of an atom?
[A] total number of protons
[B] total number of electrons in an uncharged atom
[C] Both a and b
[D] None
Show Answer
Correct Answer: C [Both a and b]
Notes:
The atomic number or proton number of a chemical element is the number of protons found in the nucleus of an atom. In an uncharged atom, the atomic number is also equal to the number of electrons.
48. What is the barrier potential for Germanium?
[A] 0.3 V
[B] 0.7 V
[C] 1 V
[D] 1.7 V
Show Answer
Correct Answer: A [0.3 V]
Notes:
The barrier potential is characteristic of the semiconductor material. It is about 0.3 V for Germanium.
49. Which of these is used as a material for making semiconductor devices?
[A] Silicon
[B] Germanium
[C] Gallium Arsenide
[D] All of the above
Show Answer
Correct Answer: D [All of the above]
Notes:
Semiconductor raw materials include germanium, gallium arsenide, silicon carbide.
50. Which of the following is correct about conductors?
[A] The conduction band and the valence band partly overlap each other
[B] There is no forbidden energy band gap between conduction band and the valence band
[C] Both a and b
[D] None of the above
Show Answer
Correct Answer: C [Both a and b]
Notes:
The conduction band and the valence band partly overlap each other and there is no forbidden energy band gap in between. The electrons from the valence band can easily move into the conduction band. Hence, large number of electrons are available for conduction.
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