Mechanical Physics MCQ question and answer with solution

81

What is an ideal fluid?

A) Very viscous B) One which obeys Newton's law of viscosity C) Compressible flow D) Frictionless and incompressible

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Answer & Solution

Answer: Option D

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82

Which one of the following is not a result of surface tension?

A) Nearly spherical drop of rain B) Capillary rise C) Removal of dirt by soap or detergent D) Flow of a liquid

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Answer & Solution

Answer: Option D

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83

Pressure inside a soap bubble is

A) More than atmospheric pressure B) Less than atmospheric pressure C) Equal to atmospheric pressure D) Half of atmospheric pressure

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Answer & Solution

Answer: Option A

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84

Match the columns.

Column I	Column II
a. Viscosity	1. Oil rises in the narrow long tube
b. Capillarity	2. tendancy to contract
c. Surface tension	3. Attractive between molecules of same substances
d. Cohesive force	4. Fluid friction

A) a-4, b-2, c-3, d-1 B) a-4, b-3, c-2, d-1 C) a-4, b-1, c-2, d-3 D) a-4, b-1, c-3, d-2

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Answer & Solution

Answer: Option C

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85

A body is floating in a liquid partly immersed. The body and the liquid are taken to moon. The body

A) will continue to float as before B) floats with greater part immersed C) floats with lesser part immersed D) will sink

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Answer & Solution

Answer: Option A

Solution:

When a body floats in a liquid, the condition of equilibrium is given by weight of the body = weight of the liquid displaced.
This relationship is based on Archimedes’ principle, which depends on the gravitational acceleration (g).

On taking the body and the liquid to the Moon, the value of g decreases equally for both the body and the displaced liquid.
Since both the weight of the body and the buoyant force depend linearly on g, the ratio between them remains the same.

Therefore, the fraction of the body immersed in the liquid does not change.
The body will continue to float as before, with the same part immersed as it was on Earth.

Hence, the correct answer is: The body will continue to float as before.

86

The force of attraction applied between molecules of the same substance is called:

A) cohesive force B) adhesive force C) capillarity D) surface tension

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Answer & Solution

Answer: Option A

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87

Viscosity is the property of liquids by virtue of which they

A) attract other molecules B) become conducting C) oppose the relative motion of its parts D) push neighbouring molecules

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Answer & Solution

Answer: Option C

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88

Assertion (A): When a ship enters a sea from a river, it rises a little.
Reason (R): The density of sea water is greater than that of river water.
In the context of the above statements, which of the following is true?

A) Both (A) and (R) are true and (R) is the correct explanation of (A) B) Both (A) and (R) are true, but (R) is not the correct explanation of (A) C) (A) is true, but (R) is false D) (A) is false, but (R) is true

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Answer & Solution

Answer: Option A

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89

In automobile hydraulic brakes work on

A) Archimedes Principle B) Newton's law of motion C) Bernoulli's Principle D) Pascal's Law

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Answer & Solution

Answer: Option D

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90

Static science is associated with

A) Dynamic situation B) Situation of rest C) Mental situation D) Data analyzing

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Answer & Solution

Answer: Option B

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Mechanical Physics MCQ question and answer with solution | Physics Gk MCQs