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 fourth state of matter called?
[A] Solid
[B] Liquid
[C] Gas
[D] Plasma
Show Answer
Correct Answer: D [Plasma]
Notes:
The fourth state of matter is called as Plasma. In Plasma, the medium is in the form of positive and negative ions. Plasma occurs in the atmosphere of stars (including the sun) and in discharge tubes.
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. What is the device used to measure the flow speed of incompressible called as?
[A] Torri-meter
[B] Bernoulli-meter
[C] Hydro-meter
[D] Venturi-meter
Show Answer
Correct Answer: D [Venturi-meter]
Notes:
The Venturi-meter is a device to measure the flow speed of incompressible fluid. It consists of a tube with a broad diameter and a small constriction at the middle.
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 happens to a body when its density is greater than the density of the fluid?
[A] it floats
[B] it sinks
[C] it stays at rest
[D] None of the above
Show Answer
Correct Answer: B [it sinks]
Notes:
The body sinks in the fluid in case its density is greater than the density of the fluid. For example, an iron nail has greater density than water, therefore it sinks in water.
58. What is the relationship between excess pressure and the radius of the bubble?
[A] are equal in value
[B] inversely proportional to each other
[C] directly proportional to each other
[D] no relationship
Show Answer
Correct Answer: B [inversely proportional to each other]
Notes:
Excess pressure is inversely proportional to the radius of bubble (or drop). It means that the pressure inside a smaller bubble is higher than inside a larger bubble.
59. Which of the following intermolecular forces enables us to write on the blackboard with a chalk?
[A] Cohesive force
[B] Adhesive force
[C] both a and b
[D] None
Show Answer
Correct Answer: B [Adhesive force]
Notes:
The force of attraction between the molecules of the different substances is called the force of adhesion. Adhesive force enables us to write on the blackboard with a chalk.
60. What is the angle of contact for pure water and glass?
[A] 0°
[B] 30°
[C] 180°
[D] 90°
Show Answer
Correct Answer: A [0°]
Notes:
Angle of contact between a liquid and a solid is defined as the angle enclosed between the tangents to the liquid surface and the solid surface inside the liquid, both the tangents being drawn at the point of contact of the liquid with the solid. Its value lies between 0° and 180°: 0°for pure water and glass, 8°for tap water and glass, 90° for water and silver
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