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.
51. Which of the following states of matter has the weakest Intermolecular forces?
[A] Solids
[B] Liquids
[C] Gases
[D] It is same in solids, liquids and gases
Show Answer
Correct Answer: C [Gases]
Notes:
The three states of matter varies from each other due to the following factors. (1) The different magnitudes of the interatomic and intermolecular forces. (2) The extent of random thermal motion of atoms and molecules of a substance (which depends upon temperature). The Intermolecular force is strongest in solids and weakest in gases.
52. In which of the following states of matter the Interatomic or intermolecular distance is fixed?
[A] Solids
[B] Liquids
[C] Gases
[D] Both a and b
Show Answer
Correct Answer: A [Solids]
Notes:
The Interatomic or intermolecular distance is fixed in the case of solids. But in cases of liquids and gases, it is not fixed.
53. What is the name given to the linear strain produced in the direction of deforming force?
[A] Linear strain
[B] Longitudinal strain
[C] Directional strain
[D] Zero strain
Show Answer
Correct Answer: B [Longitudinal strain]
Notes:
Linear strain: If the deforming force produces a change in length alone, the strain produced in the body is called linear strain or tensile strain. Linear strain in the direction of deforming force is called longitudinal strain and in a direction perpendicular to force is called lateral strain.
54. What will happen if a wire of length L is cut into two or more parts?
[A] each part can hold half the weight as full length wire
[B] each part can hold the same weight as full length wire
[C] each part can hold twice the weight as full length wire
[D] None of the above
Show Answer
Correct Answer: B [each part can hold the same weight as full length wire]
Notes:
If a wire of length L is cut into two or more parts, then it’s each part can hold the same weight. Since breaking force is independent of the length of wire.
55. Which of the following is the correct equivalent of 1 atmosphere?
[A] 1 atmosphere = 1.013 × 105Pa
[B] 1 atmosphere = 1.013 × 104Pa
[C] 1 atmosphere = 1.013 × 103Pa
[D] 1 atmosphere = 1.013 × 102Pa
Show Answer
Correct Answer: A [1 atmosphere = 1.013 × 105Pa]
Notes:
A common unit of pressure is the atmosphere (atm), i.e. the pressure exerted by the atmosphere at sea level (1 atm = 1.013 × 105Pa).
56. On which of these factors, the buoyancy depends?
[A] Density of the fluid
[B] Volume of the body
[C] Both a and b
[D] None of the above
Show Answer
Correct Answer: C [Both a and b]
Notes:
The buoyancy depends upon the following two factors: 1. The volume of the body submerged in the fluid. 2. The density of fluid in which the body is immersed
57. What is the main cause of capillarity?
[A] difference in weight of fluids
[B] pressure difference
[C] temperature difference
[D] velocity gradient
Show Answer
Correct Answer: B [pressure difference]
Notes:
The main cause of capillarity is the difference in pressures on two sides of (concave and convex) curved surface of liquid.
58. Which of the following is NOT an example of capillary action?
[A] Rise of ink in the fine pores of blotting paper
[B] soaking of water by a towel
[C] Wood swells in rainy season due to rise of moisture
[D] None of the above
Show Answer
Correct Answer: D [None of the above]
Notes:
Examples of capillarity : (i) Ink rises in the fine pores of blotting paper leaving the paper dry. (ii) A towel soaks water. (iii) Oil rises in the long narrow spaces between the threads of a wick. (iv) Wood swells in rainy season due to rise of moisture from air in the pores.
59. Which is the effect of increase in impurities on the surface tension of the liquid?
[A] It increases
[B] It decreases
[C] It may increase or decrease
[D] No change
Show Answer
Correct Answer: C [It may increase or decrease]
Notes:
The presence of impurities considerably affect the force of surface tension, depending upon the degree of contamination. A highly soluble substance like sodium chloride when dissolved in water, increases the surface tension of water. But the sparingly soluble substances like phenol when dissolved in water, decreases the surface tension of water.
60. Which of the following is the S.I. unit of density?
[A] m-2
[B] m-3
[C] kg m-2
[D] kg m-3
Show Answer
Correct Answer: D [ kg m-3 ]
Notes:
The SI unit of density is kg m-3. It is a positive scalar quantity. The Gaussian unit of density is the gram per cubic centimeter which is equivalent to a gram per milliliter [1 g/cm3 = 1 g/ml].
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