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 law states that if two systems are in thermal equilibrium with a third system separately, then they are in thermal equilibrium with each other?
[A] First law of Thermodynamics
[B] Zeroth law of Thermodynamics
[C] Second law of Thermodynamics
[D] Third law of Thermodynamics
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Correct Answer: B [Zeroth law of Thermodynamics]
Notes:
Zeroth Law of Thermodynamics states that ‘two systems in thermal equilibrium with a third system separately are in thermal equilibrium with each other’.
42. How many joules are there in one calorie?
[A] 3.186 J
[B] 4.186 J
[C] 5.186 J
[D] 6.186 J
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Correct Answer: B [4.186 J]
Notes:
There are 4.186 J in once calorie.
43. 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.
44. Where will be the image formed by a convex lens when the object is placed at the focus?
[A] No image is formed
[B] At focus
[C] Between focus and optical centre
[D] At infinity
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Correct Answer: D [At infinity]
Notes:
The image is formed at infinity by a convex lens when the object is placed at the focus.
45. What is the size of the image formed by a concave mirror when the object is at focus?
[A] Enlarged
[B] Point sized
[C] Same size
[D] Highly enlarged
Show Answer
Correct Answer: D [Highly enlarged]
Notes:
Highly enlarged image is formed by a concave mirror when the object is at focus.
46. Which of the following mirrors is commonly used as rear-view mirror in a vehicle?
[A] Concave mirror
[B] Convex mirror
[C] Plain mirror
[D] None of the above
Show Answer
Correct Answer: B [Convex mirror]
Notes:
Convex mirrors are commonly used as rear-view (wing) mirrors in vehicles. Convex mirrors are preferred because they always give an erect, though diminished, image.
47. What is the work done to move a unit charge from point to another called as?
[A] Current
[B] Resistance
[C] Conductance
[D] Potential Difference
Show Answer
Correct Answer: D [Potential Difference ]
Notes:
Work done to move a unit charge from one point to another is known as the electric potential difference between two points. Potential difference (V) = Work done (W)/Charge (Q) Volt is the SI unit of electric potential difference named after Alessandro Volta
48. What do we call the rate at which electric energy is dissipated or consumed in an electric circuit?
[A] Conductance
[B] Power
[C] Resistance
[D] Potential Difference
Show Answer
Correct Answer: B [Power ]
Notes:
Power is the rate at which electric energy is dissipated or consumed in an electric circuit.
49. What is the device used to measure the cell potential?
[A] Ammeter
[B] Voltmeter
[C] Wattmeter
[D] None of the above
Show Answer
Correct Answer: B [Voltmeter]
Notes:
The voltmeter measures the cell potential, denoted by Ecell which is the potential difference between two half cells.
50. What do we call the cell that converts the potential energy from a fuel into electricity?
[A] Electrolytic cell
[B] Galvanic cell
[C] Dry cell
[D] Fuel cell
Show Answer
Correct Answer: D [Fuel cell]
Notes:
A fuel cell is an electrochemical cell that converts the potential energy from a fuel into electricity through an electrochemical reaction of hydrogen fuel with oxygen or another oxidizing agent
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