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Question (1)

QN0035680

Water rises to a height ' ' in a capillary tube. If the length of capaillary tube above the surface of water is made less than ' ' then :

(A)
water rises upto the top of capillary tube and stays there without overflowing
(B)
water rises upto a point a little below the top and stays there
(C)
water does not rise at all.
(D)
Water rises upto the tip of capillary tube and then starts overflowing like fountain.

Correct Answer: A

Explanation:

Water rises upto the top of capillary tube and stays there without overflowing.

According to Jurin's Law,

So if ' ' decreases, radius ' ' increases.

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Question (2)

QN0035681

The cylindrical tube of a spray pump has radius, , one end of which has fine holes, each of radius . If the speed of the liquid in the tube is , the speed of the ejection of the liquid through the holes is :

(A)
(B)
(C)
(D)

Correct Answer: A

Explanation:

Inflow rate of volume of the liquid = Outflow rate of volume of the liquid

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Question (3)

QN0035682

A U tube with both ends open to the atmosphere, is partially filled with water. Oil, which is immiscible with water, is poured into one side until it stands at a distance of above the water level on the other side. Meanwhile the water rises by from its original level (see diagram). The density of the oil is

(A)
(B)
(C)
(D)

Correct Answer: C

Explanation:

Here,

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Question (4)

QN0035683

A small sphere of radius ' ' falls from rest in a viscous liquid. As a result, heat is produced due to viscous force. The rate of production of heat when the sphere attains its terminal velocity, is proportional to

(A)
(B)
(C)
(D)

Correct Answer: D

Explanation:

Power = rate of production of heat =F.V stoke's formula)

Power

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Question (5)

QN0035684

A small hole of area of cross-section is present near the bottom of a fully filled open tank of height . Taking , the rate of flow of water through the open hole would be nearly:

(A)
(B)
(C)
(D)

Correct Answer: A

Explanation:

Volumetric flow rate of liquid

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Question (6)

QN0035685

A soap bubble, having radius of , is blown from a detergent solution having a surface tension of . The pressure inside the bubble equals at a point below the free surface of water in a container. Taking , density of water , the value of is:

(A)
(B)
(C)
(D)

Correct Answer: C

Explanation:

Pressure inside the soap bubble

And pressure at a point below the surface of water

By equating these pressure we get,

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Question (7)

QN0035686

A capillary tube of radius is immersed in water and water rises in it to a height . The mass of the water in the capillary is . Another capillary tube of radius is immersed in water. The mass of water that will rise in this tube is :

(A)
(B)
(C)
(D)

Correct Answer: B

Explanation:

Force of surface tension balances the weight of water in capillary tube.

Here, and are constants.

So,

Let and be the mass of water in two capillary tube.

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Question (8)

QN0035687

The velocity of a small ball of mass and density , when dropped in a container filled with glycerine becomes constant after some time. If the density of glycerine is , then the viscous force acting on the ball will be

(A)
(B)
(C)
(D)

Correct Answer: B

Explanation:

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Question (9)

QN0035688

A spherical ball is dropped in a long column of a highly viscous liquid. The curve in the graph shown, which represents the speed of the ball as a function of time is:

(A)
B
(B)
C
(C)
D
(D)
A

Correct Answer: B

Explanation:

When ball is dropped in highly viscous fluid, the ball's velocity will increase untill it becomes equal to terminal velocity and after attaining terminal velocity it moves downward with constant velocity so, graph will be like as shown below

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Question (10)

QN0035689

If a soap bubble expands, the pressure inside the bubble:

(A)
increases
(B)
remains the same
(C)
is equal to the atmospheric pressure
(D)
decreases

Correct Answer: D

Explanation:

Pressure inside soap bubble,

Clearly,

So, if bubble expands, pressure decreases.

Alternative method :

Here, cons. remains same

, as

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Question (1)

Water rises to a height ' ' in a capillary tube. If the length of capaillary tube above the surface of water is made less than ' ' then :

Explanation:

Link:

Question (2)

The cylindrical tube of a spray pump has radius, , one end of which has fine holes, each of radius . If the speed of the liquid in the tube is , the speed of the ejection of the liquid through the holes is :

Explanation:

Link:

Question (3)

Explanation:

Link:

Question (4)

A small sphere of radius ' ' falls from rest in a viscous liquid. As a result, heat is produced due to viscous force. The rate of production of heat when the sphere attains its terminal velocity, is proportional to

Explanation:

Link:

Question (5)

A small hole of area of cross-section is present near the bottom of a fully filled open tank of height . Taking , the rate of flow of water through the open hole would be nearly:

Explanation:

Link:

Question (6)

A soap bubble, having radius of , is blown from a detergent solution having a surface tension of . The pressure inside the bubble equals at a point below the free surface of water in a container. Taking , density of water , the value of is:

Explanation:

Link:

Question (7)

A capillary tube of radius is immersed in water and water rises in it to a height . The mass of the water in the capillary is . Another capillary tube of radius is immersed in water. The mass of water that will rise in this tube is :

Explanation:

Link:

Question (8)

The velocity of a small ball of mass and density , when dropped in a container filled with glycerine becomes constant after some time. If the density of glycerine is , then the viscous force acting on the ball will be

Explanation:

Link:

Question (9)

A spherical ball is dropped in a long column of a highly viscous liquid. The curve in the graph shown, which represents the speed of the ball as a function of time is:

Explanation:

Link:

Question (10)

If a soap bubble expands, the pressure inside the bubble:

Explanation:

Link:

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