Class 8 Science: Pressure — Practice Questions with Answers

Which of the following correctly defines pressure?

1. The force acting on a unit area of a surface
2. The total force acting on a surface
3. The area over which a force is spread
4. The force multiplied by the area of the surface

What is the SI unit of pressure?

1. N/m²
2. N
3. N/m
4. N·m

A sharp knife cuts vegetables more easily than a blunt knife because

1. the sharp edge has a very small area, so the same force produces much greater pressure
2. the sharp edge increases the force applied by our hand
3. the sharp edge spreads the force over a larger area
4. the sharp knife is heavier than the blunt knife

A force of 100 N acts on a surface of area 2 m². What is the pressure on the surface?

1. 50 N/m²
2. 200 N/m²
3. 100 N/m²
4. 0.02 N/m²

A camel can walk easily on loose sand because its broad feet

1. increase the area of contact and reduce the pressure on the sand
2. increase the pressure exerted on the sand
3. reduce the weight of the camel
4. reduce the area of contact with the sand

A tall vessel full of water has three identical holes: one near the top, one in the middle, and one near the bottom. Water rushes out with the greatest force from the hole near the bottom because

1. the pressure of a liquid increases with depth
2. the pressure of a liquid is the same at all depths
3. water near the bottom is heavier than water near the top
4. air pressure acts only at the bottom of the vessel

When we suck through a straw dipped in a glass of juice, the juice rises up into our mouth. What actually pushes the juice up the straw?

1. The atmospheric pressure acting on the surface of the juice in the glass
2. The pulling force of our tongue acting directly on the juice
3. The juice becoming lighter inside the straw
4. The straw attracting the juice upwards

A box weighing 400 N can be placed on the ground either on its larger face of area 2 m² or on its smaller face of area 0.5 m². The pressure exerted on the ground by the smaller face is

1. four times the pressure exerted by the larger face
2. the same as the pressure exerted by the larger face
3. one-fourth of the pressure exerted by the larger face
4. twice the pressure exerted by the larger face

When a small hole is made in the side wall of a bottle completely filled with water, water spurts out sideways through the hole. This observation shows that

1. liquids exert pressure on the walls of their container
2. liquids exert pressure only at the bottom of their container
3. air inside the bottle pushes the water out
4. water always flows in the sideways direction

A force of 50 N acts on the tip of a nail being hammered into a wall. If the area of the tip is 0.0001 m², what pressure does the nail tip exert on the wall?

1. 500000 N/m²
2. 50000 N/m²
3. 5000 N/m²
4. 0.000002 N/m²

Some mountaineers get nose bleeding at very high altitudes. The most likely reason is that

1. the atmospheric pressure outside becomes much lower than the pressure of the blood inside the body
2. the atmospheric pressure becomes much higher at high altitudes and presses on the nose
3. there is more oxygen at high altitudes, which increases the flow of blood
4. the blood inside the body stops exerting any pressure at high altitudes

The force acting on a surface is doubled, and at the same time the area of the surface is also doubled. What happens to the pressure on the surface?

1. It remains the same
2. It becomes double
3. It becomes four times
4. It becomes half