Mechanical Properties Of Fluids CBSE Questions & Answers

Mechanical Properties Of Fluids

This is Physics Class 11 Mechanical Properties of Fluids CBSE Questions & Answers. There are 15 questions in this test with each question having around four answer choices.

Questions & Answers

1
A wooden block is taken to the bottom of a deep, calm lake of water and then released. It rises up with a
  • A
    decreasing acceleration
  • B
    constant acceleration
    Correct
  • C
    decreasing velocity
  • D
    constant velocity
2
A man in a lift is holding a can filled with water but having a hole in its bottom. When will the drainage of water be maximum?
  • A
    When the lift is going up with acceleration
    Correct
  • B
    When the lift is stationary
  • C
    when the lift is going down with acceleration
  • D
    when the lift goes down with uniform velocity
3
In old age, arteries carrying blood in the human body, become narrow resulting in an increase in the blood pressure. This follows from
  • A
    Archimedes principle
  • B
    Stoke’s law
  • C
    Bernoulli’s principle
  • D
    Pascal’s law
    Correct
4
Soap helps in better cleansing of clothes because
  • A
    it reduces the surface tension of solution
    Correct
  • B
    it absorbs the dirt
  • C
    it does not reduce the surface tension of solution
  • D
    chemicals of soap change
5
If two soap bubbles of different radii are in communication with each other
  • A
    air flows from the smaller bubble into the larger one and large bubble grows at the expense of the smaller one
    Correct
  • B
    air flows from the larger into the smaller bubble until the radius of the smaller one becomes half that of the larger one
  • C
    air flows from the larger bubble into the smaller one until the two bubbles are of equal size
  • D
    the sizes of the bubbles remain unchanged
6
More liquid rises in a thin tube because of
  • A
    smaller value of S.T
  • B
    larger value of surface tension
  • C
    smaller value of radius
    Correct
  • D
    larger value of radius
7
The surface tension of soap solution is 25 x \({\rm{1}}{0^{ - {\rm{3}}}}\) \({\rm{N}}{{\rm{m}}^{ - {\rm{1}}}}\). The excess pressure inside a soap bubble of diameter 1 cm is
  • A
    15 Pa
  • B
    20 Pa
    Correct
  • C
    10 Pa
  • D
    5 Pa
8
When a soap bubble is charged
  • A
    it expands
    Correct
  • B
    it disappears
  • C
    it does not undergo any change in size
  • D
    it contracts
9
A drop of oil is placed on the surface of water. Which of the following statements is correct?
  • A
    it will float as a distorted drop on the water surface
  • B
    it will remain on it as a sphere
  • C
    it will spread as a thin layer
    Correct
  • D
    it will partly changed to spherical droplets and partly as thin film
10
Small droplets of liquid are usually more spherical in shape than larger drops of the same liquid because
  • A
    force of gravity and force of surface tension act in the same direction and are equal
  • B
    force of gravity predominates the force of surface tension
  • C
    force of surface tension predominates the force of gravity
    Correct
  • D
    force of surface tension is equal and opposite to the force of gravity
11
Water rises to a height of 16.3 cm in a capillary of height 18 cm above the water level. If the tube is suddenly cut at a height of 12 cm
  • A
    the height of the water in the capillary will be 10.3 cm
  • B
    water will stay at a height of 12 cm in the capillary tube
  • C
    water will come as a fountain from the capillary tube
  • D
    water will flow down the sides of the capillary tube
    Correct
12
A soap bubble has radius r and the surface tension of the soap film is T. The energy needed to double the diameter of the bubble without change of temperature is
  • A
    \(8\pi {r^2}T\)
  • B
    1\(4\pi {r^2}T\)
  • C
    \(4\pi {r^2}T\)
  • D
    \(24\pi {r^2}T\)
    Correct
13
A liquid drop of radius R is broken up into N small droplets. The work done is proportional to
  • A
    N\(^{ - 0.{\rm{5}}}\)
  • B
    N
  • C
    N\(^{ - {\rm{1}}/{\rm{3}}}\)
    Correct
  • D
    N\(^{ - {\rm{2}}/{\rm{3}}}\)
14
An air bubble of radius r is formed inside a tank of water of depth h. The atmospheric pressure is equal to a water column of height H. the pressure inside the bubble is
  • A
    A.H + h
  • B
    H + h + 2T/r
    Correct
  • C
    H + h + 4T/r
  • D
    H + h + T/r
15
It is easier to spray water to which soap is added, because
  • A
    addition of soap to water increases its density
  • B
    addition of soap to water makes surface tension of water zero
  • C
    addition of soap to water increases surface tension of water
  • D
    addition of soap to water decreases surface tension of water
    Correct