Factors Affecting Pressure

Q.

State three factors on which the pressure at a point in a liquid depends.

Q.

What is the relation between compressibility and Bulk modulus?

Q.

Why is it difficult to hold a school bag having a strap made of a thin and strong string?

Q.

Pressure in liquids does not depend on the surface area.

How is this possible as pressure is thrust/area

Q. What height of water column will exert the pressure on its base, same as that by 76 cm of mercury column ? (density of mercury 13.6 g cm^-3)

Q. Calculate the approximate height (h) of Earth's atmosphere extending above the surface of the Earth, assuming the density of air to be uniform [$1.3kg{m}^{-3}$] and pressure at the surface of Earth to be ${10}^{5}Pa$. (Assume the Earth to be perfectly spherical and no variation in 'g' due to height).

1. $8km<h<9km$

2. $6km<h<7km$

3. $5km<h<6km$

4. $7km<h<8km$

Q.

As we climb up a mountain, the atmospheric pressure

1. increases

2. decreases

3. remains same

4. first increases then decreases

Q.

When a ship goes from seawater to river water, it displaces

1. More water to change the upthrust on it.

2. Less water to change the upthrust.

3. More water to increase the stability.

4. Equal water.

Q.

The pressure of water on the ground floor is 40, 000 Pa and on the first floor is 10, 000 Pa. Find the height of the first floor. (Take : density of water = 1000 kg $m^{-3}$, g =10 m $s^{-2}$

Q.

Pressure increases with altitude.

1. True

2. False

Q.

Explain why wooden or concrete sleepers are kept below the railway line.

Q.

A man of mass 60 kg stands on a weighing machine of area 225 cm². The pressure exerted by him is: Take g = 10 m/s2.

1. 266.67 Pa

2. 266666.7 Pa

3. 26666.7 Pa

4. 26.667 Pa

Q.

Pressure can be increased by increasing the area on which it is exerted.

1. True
2. False

Q.

Convert 1 mm of Hg into pascal. Take density of Hg = 13.6 $\times {10}^3$ kg $m^{-3}$ and g= 9.8 m $s^{-2}$.

Q.

A sprinter prefers shoes fitted with spikes. Why?

Q.

(a) Calculate the height of a water column which will exert on its base the same pressure as the 70 cm column of mercury. Density of mercury is 13.6 g $c{m}^{-3}$.

(b) Will the height of the water column in part (a) change if the cross section of the water column is made wider ?

Q.

A force of 60 N acts on a body having an area of cross-section 5 cm². Calculate the pressure exerted by the body.

Q.

At sea level, the atmospheric pressure is 1.04 $\times {10}^{5}Pa$. Assuming g = 10 $m{s}^{-2}$ and density of air to be uniform and equal to 1.3 kg $m^{-3}$, find the height of the atmosphere.

Q.

Why s gas bubble released at the bottom of a lake grows in size as it rises to the surface of the lake

Q.

The pressure exerted by water (density = 103 kg/m3) on the bottom surface (2m × 4m) of tank having dimensions 2m × 4m × 2m is

1. 2.96 × 10⁵ Pa

2. 1.80 × 10⁴ Pa

3. 1.96 × 10⁴ Pa

4. 1.96 × 10⁵ Pa

Q.

A barometer will show a greater reading when taken down into a coal mine. Why?

Q.

A tall vertical cylinder filled with water is kept on a horizontal table top. Two small holes A and B are made on the wall of the cylinder, A near the middle and B just below the free surface of water. State and explain your observation.

Q.

The force acting perpendicular to the surface of the object is called _____________.

Q.

A force of $40N$ is applied over a surface area of $2.5m^2$ . Calculate the pressure.

Q.

Why the bubbles exhaled by scuba divers grow as they approaches the surface of the ocean?

Q. Why do trucks have more tires?

Q.

How does pressure change with respect to change in area?

Q.

With the increases in the area of contact the pressure________.

Q.

How does the pressure at a certain depth in sea water differ from that at the same depth in river water? Explain your answer.

Q.

Pressure increases on increasing the area of contact.

1. True
2. False