Atmospheric Pressure

Q.

When a balloon is inflated by blowing air into it, What happens to the balloon when it is inflated by blowing air into it?

Q.

What factors affect the boiling point ?

Q. A barometer tube reads $75\text{cm}$ of $Hg$. If the tube is gradually inclined at an angle of ${30}^{\circ }$ with the horizontal, keeping the open end in the mercury container, find the length of the mercury column in the barometer tube.

1. $75\text{cm}$
2. $92.5\text{cm}$
3. $86.7\text{cm}$
4. $150\text{cm}$

Q. If height of mercury in a barometer is $760\text{mm}$ at any location. If mercury is replaced by water then height of water will be

1. $6.883\text{m}$
2. $10.336\text{m}$
3. $5.251\text{m}$
4. $8.521\text{m}$

Q. The height of a mercury barometer is $75\text{cm}$ at sea level and $50\text{cm}$ at the top of a hill. Ratio of density of mercury to that of air is ${10}^4$. The height of the hill is

1. $1.25\text{km}$
2. $2.5\text{km}$
3. $250\text{m}$
4. $750\text{m}$

Q.

Two narrow bores of diameters 3.0 mm and 6.0 mm are joined together to form a U-tube open at both ends. If the U-tube contains water, what is the difference in its levels in the two limbs of the tube? Surface tension of water at the temperature of the experiment is $7.3\times {10}^{–2}N{m}^{–1}$. Take the angle of contact to be zero and density of water to be $1.0\times {10}^{3}kg{m}^{–3}(g=9.8m{s}^{–2})$.

Q.

Does boiling point increase with the vapour pressure

Q. Consider the barometer shown in figure. If a small hole is made at point $A$ in the barometer tube, then

1. Mercury will come out from this hole after $10\text{sec}$
2. Mercury will not come out from this hole
3. First, mercury will come out and then stop after $10\text{sec}$
4. Mercury will come out from this hole after $15\text{sec}$

Q. Torricelli's barometer uses mercury of density $13.6\times {10}^3{\text{kg/m}}^3$. If mercury is replaced by wine of density $984{\text{kg/m}}^3$, then determine the height of the wine column for normal atmospheric pressure.

1. $760\text{m}$
2. $76\text{m}$
3. $10.5\text{m}$
4. $105\text{m}$

Q.

The height of a mercury column in a barometer in a Calcutta library was recorded to be 75cm.Calculate this pressure in SI and CGS units using the following data : Specific gravity of mercury = 13.6, Density of water = 10³ kg/m³, g = 9.8 m/s² at Calcutta .Pressure = hpg in usual symbols.

Q. A barometer tube reads $76\text{cm}$ of $\text{Hg}$. If the tube is gradually inclined at an angle of ${30}^{\circ }$ with horizontal, then find the length of the mercury column in the barometer tube.

1. $142\text{cm}$
2. $152\text{cm}$
3. $132\text{cm}$
4. $122\text{cm}$

Q.

A spherical ball contracts in volume by $0.01\%$ when subjected to normal uniform pressure $100atm$. The Bulk modulus of its material is

Q. In the manometer as shown, $2$ immiscible fluids - mercury $(\rho =13600{\text{kg/m}}^3)$ and water $(\rho =1000{\text{kg/m}}^3)$ are used as manometric fluids. The water end is exposed to the atmosphere $\left(100\text{kPa}\right)$ and the mercury end is exposed to a gas. At this position, the interface between the fluids is at the bottom most point of the manometer. The value of $h$ is found to be $9.45\text{m}$. The height of the mercury column is given to be $75\text{cm}$. Find the gauge pressure of the gas. $(g=9.8{\text{m/s}}^2)$

1. $100\text{kPa}$
2. $50\text{kPa}$
3. $200\text{kPa}$
4. $0\text{kPa}$

Q.

Atmospheric pressure at sea level is 76 cm of mercury. Calculate the vertical height of the air column exerting the above pressure. Assume the density of air is 1.29 kg/m³ and that of mercury is 13600 kg/m³. Why the height calculated by you is far less than the actual height of the atmosphere?

Q. Select the correct statement :-
(i) Barometer is used to measure atmospheric pressure
(ii) Manometer is used to measure gauge pressure of a fluid inside a container

1. (i) Only
2. (ii) Only
3. Both (i) & (ii)
4. None of these

Q. Which of the following statements is/are correct?
(i) A simple U-tube manometer can measure negative gauge pressures.
(ii) Both ends of a U-tube manometer are exposed to the atmosphere. There exists a possibility that the height difference in the manometer is non-zero.

1. Only (i) is correct
2. Only (ii) is correct
3. Both (i) and (ii) are correct
4. None of these are correct

Q. A student wants to find the absolute pressure of water at a point below the surface of water. He has a barometer and a manometer pressure gauge. The barometer reads $1.3152\text{bar}$ whereas the manometer pressure gauge reads $0.3152\text{bar}$. What is the absolute pressure? (Assume that pressure at one end of the manometer is atmospheric.)

1. $1\text{bar}$
2. $1.6304\text{bar}$
3. $0.3152\text{bar}$
4. $1.3152\text{bar}$

Q.

A U-tube contains water and methylated spirit separated by mercury. The mercury columns in the two arms are in level with 10.0 cm of water in one arm and 12.5 cm of spirit in the other. What is the specific gravity of spirit?

Q. A barometer kept in an elevator at rest reads $76\text{cm}$ of $Hg$. If the elevator starts accelerating downwards, then the atmospheric pressure measured by the barometer (w.r.t column of mercury) in the elevator is:

1. $76\text{cm}$
2. $<76\text{cm}$
3. zero
4. $>76\text{cm}$

Q.

A faulty barometer contains certain amount of air and saturated water vapour. It reads 74.0 cm when the atmospheric pressure is 76.0 cm of mercury and reads 72.10 cm when the atmospheric pressure is 74.0 cm of mercury. Saturation vapour pressure at the air temperature = 1.0 cm of mercury. Find the length of the barometer tube above the mercury level in the reservoir.

Q.

Does high vapour pressure mean a high boiling point?

Q. The pans of a physical balance are in equilibrium. If air is blown under a pan, that pan will move down.

1. False
2. True

Q. Consider the barometer shown in figure. Density of mercury is $\rho$. A small hole is made at point $S$ as shown. The mercury comes out from this hole with speed $v$ equal to:

1. $\sqrt{2gH}$
2. $\sqrt{2g(H-h)}$
3. $\sqrt{2gh}$
4. None of the above

Q.

If the pressure exerted on gas is increased by 4 times and temperature is increased by 9 times, what will be the change in volume occupied by the gas?

Q. 49. an air bubble inside a cubical blockof glass side4.5cmseems to beat2cm from one faceand 1cm from other faceopposite to first when viewednormally.what is real dist of bubble from first face?

Q.

An inverted tube barometer is kept in a lift moving vertical upward with an acceleration a. The density of mercury is $\rho$ and acceleration due to gravity is g. If the atmospheric pressure be $P_o$ then

1. 

2. 

3. 

4. 

Q. A solid body is found floating in water with a/b of its volume submerged. The same solid is found floating in a liquid with a/b of its volume above the liquid surface. The specific gravity of the liquid is

Q.

Food is cooked faster in Delhi when compared to Shimla. Explain.

Q. One atmospheric pressure (atm) is equal to

1. 101325 Pa
2. 1013.25 Pa
3. 101.325 Pa
4. 10.1325 Pa

Q.

Explain why holes are made in hanging banners and hoardings.