Tag: fluids

Quizzes (14) Questions (63)

Questions Related to fluids

Multiple choice various types of barometer fluids physics

In a certain region of space, there are n molecules per unit volume. The temperature of the gas T. The pressure of the gas will be: 

  1. $nRT$
  2. $nkT$
  3. $\dfrac{{nT}}{k}$
  4. $\dfrac{{nT}}{R}$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The ideal gas law is PV = nRT, where n is the number of moles. In terms of number of molecules N, it is PV = NkT, where k is the Boltzmann constant. Dividing by volume V gives P = (N/V)kT, where N/V is the number density n, leading to P = nkT.

Multiple choice various types of barometer fluids physics

How is the barometric height of a simple barometer affected if
(a) its tube is pushed down into the trough of mercury?
(b) its tube is slightly tilted form vertical?
(c) a drop of liquid is inserted inside the tube?

  1. (a) remains unaffected (b) increases (c) decreases

  2. (a) decreases (b) increases (c) decreases

  3. (a) increases (b) remains unaffected (c) increases

  4. (a) remains unaffected (b) remains unaffected (c) decreases
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Below are the answers:
(a) Mercury in the tube adjusts until the weight of the mercury column balances the atmospheric force exerted on the reservoir. High atmospheric pressure places more force on the reservoir, forcing mercury higher in the column. Low pressure allows the mercury to drop to a lower level in the column by lowering the force placed on the reservoir.
When the tube is pushed down into the trough of mercury the height of mercury column above the surface of the bottom surface remains the same. 


(b) When the tube is slightly tilted form vertical, there is no change in the height of the mercury in the tube.

(c) If the vacuum is replaced with a drop, then the drop will exert some pressure on the mercury and there will be inaccurate readings on the barometer. The barometric height is decreased in this case. So, vacuum is present on top of the mercury inside the tube.

Multiple choice various types of barometer fluids physics

Which of the following is not a reason why mercury is preferred as a barometric liquid?

  1. Mercury has high density

  2. Mercury does not wet the glass

  3. Mercury is opaque and shiny

  4. Mercury is poisonous
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

1) It has $13.5$ times higher density than water
2) It doesn't stick to the glass walls of tube like water does.

3) It is opaque and shiny

Multiple choice various types of barometer fluids physics

Atmospheric pressure at a place is $66cm$ of mercury. This place is

  1. $1250m$ above sea level
  2. $1250m$ below sea level
  3. $125m$ above sea level

  4. at the sea level
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Atmospheric pressure at the place is equivalent to that of $66cm$ of mercury.
We know that atmospheric pressure at the sea level is equivalent to that of $76cm$ of mercury.
So, pressure at that place is less by $(76-66)=10cm$ of mercury.
We know that atmospheric pressure decreases by $1cm$ for every $125m$ increase in altitude.
So, the concerned place is $(125 \times 10)m=1250m$ above the sea level.

Multiple choice various types of barometer fluids physics

If the mass of the sheet at the top of the aneroid barometer used as an altimeter is increased, what will be the effect on the reading?

  1. It will reduce.

  2. It will increase.

  3. No effect.

  4. Can't be determined
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

If the top sheet in an aneroid barometer is heavier, it will displace lesser. So, it gives reading corresponding to a lower pressure with a lighter thin sheet. Lower pressure is observed at more heights and hence, the reading of the altimeter will increase.

Multiple choice various types of barometer fluids physics

Water vaporizes under vacuum conditions. Mark the statement which is correct with respect to using water as a barometric fluid.

  1. It will show the true atmospheric pressure.

  2. It will be clearly seen in the glass tube.

  3. It will not show true atmospheric pressure.

  4. None
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

WATER VAPORISES UNDER VACUUM CONDITIONS.THUS WATER BAROMETER WILL NOT SHOW TRUE ATMOSPHERIC PRESSURE.

Multiple choice various types of barometer fluids physics

Atmospheric pressure at a certain place is equivalent to $78cm$ of mercury. That place is

  1. $250m$ above sea level
  2. $250m$ below sea level
  3. $125m$ above sea level

  4. at the sea level
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Atmospheric pressure at that place is $78cm$ of mercury.
We know that the atmospheric pressure at the sea level is $76cm$ of mercury.
This means, this place has an atmospheric pressure $(78-76)cm=2cm$ more than the atmospheric pressure at the sea level.
We know that the atmospheric pressure increases by $1cm$ for every $125m$ decrease in height.
So, this place is $(125 \times 2)m=250m$ below sea level.

Multiple choice various types of barometer fluids physics
Gradual fall in the mercury level in a barometer indicates

  1. possibility of rain

  2. possibility of thunderstorm

  3. fair weather

  4. dry and sunny weather
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Gradual fall in the mercury level occurs at low pressure- If there is too much moisture in the air, indicates the possibility of rain

Multiple choice various types of barometer fluids physics

Which is the most accurate instrument to measure pressure and is used as a standard?

  1. Aneroid Barometer

  2. Mercury Barometer

  3. Barograph

  4. Manometer
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Answer is B

In the mercury barometer, atmospheric pressure balances a column of mercury, the height of which can be precisely measured. To increase their accuracy, mercury barometers are often corrected for ambient temperature and the local value of gravity.

Multiple choice physics fluids pressure in fluids pressure in liquids introduction to pressure

A barometer which measures atmospheric pressure more accurately is ..........

  1. Fortin's barometer

  2. mercury barometer

  3. anaeroid barometer

  4. Torricelli barometer
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

A barometer which measures atmospheric pressure most accurately is mercury barometer.

Hence, option B is correct.