Pressure O level

A gas is trapped inside a cylinder by a movable piston. The length of the gas column is 20cm and the pressure inside the cylinder is p.

The piston is pulled out a distance of 30cm, so that the length of the gas column is now 50cm. The temperature of the gas does not change. What is the new pressure of the gas?

• 0.40p

• 0.60p

• 1.5p

• 2.5p

The base of a rectangular storage tank is 2.0m by 3.0m. The tank is filled with paraffin to a depth of 3.0m.

The density of paraffin is 800kg/m³ and the gravitational field strength is 10N/kg. What is the pressure at the bottom of the tank due to the paraffin?

• 2400Pa

• 14400Pa

• 24000Pa

• 144000Pa

The diagram shows a manometer containing mercury that is sealed at one end.

What happens to the distance h when the manometer is taken to the top of a mountain?

• It decreases, because atmospheric pressure decreases with height.

• It decreases, because atmospheric pressure increases with height.

• It increases, because atmospheric pressure decreases with height.

• It increases, because atmospheric pressure increases with height.

Which graph shows the total external pressure acting on a submarine at different depths below the surface of the sea?

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The diagrams show, to the same scale, the vertical sections of a set of circular vessels, each containing the same depth of water.

Which one of the following statements is correct?

• The water exerts the greatest pressure on the base of vessel P.

• The water exerts the greatest pressure on the base of vessel S.

• The water exerts the same force on the base of each vessel.

• The water exerts the same pressure on the base of each vessel.

An airtight container holds a fixed mass of gas. Its pressure and volume are measured on four occasions when the temperature is 20°C. The results are shown in the table. Three sets of readings are correct. Which set of readings is not correct?

• A

• B

• C

• D

The diagram shows a glass block resting on a table top

The area of the block in contact with the table is X and the area of the table top is Y.

The weight of the block is P and the weight of the table is Q.

Which expression gives the pressure exerted on the table by the block?

• P/X

• P/Y

• Q/X

• Q/Y

The diagrams show a simple mercury barometer

Which diagram shows the distance to be measured to find atmospheric pressure?

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Bubbles of gas, escaping from the mud at the bottom of a deep lake, rise to the surface.

As the bubbles rise they get larger. Why is this?

• Atmospheric pressure on the bubbles decreases.

• Atmospheric pressure on the bubbles increases

• Water pressure on the bubbles decreases.

• Water pressure on the bubbles increases

The system shown in the diagram contains a liquid.

A downward force of 80N is exerted on piston K.

What will be the upward force exerted by the liquid on piston L?

• 1 N

• 4 N

• 80 N

• 1600 N