Test: Pressure - UPSC MCQ

Pressure is defined as the force applied per unit area. It is the ratio of force to the area over which the force is distributed.

The SI unit of pressure is the Pascal (Pa). It is named after the French mathematician and physicist Blaise Pascal.

The pressure exerted by a fluid is affected by factors such as the density of the fluid, the depth of the fluid, and the acceleration due to gravity. Temperature does not directly affect the pressure exerted by a fluid.

Atmospheric pressure decreases with increasing altitude. This is because the weight of the air above decreases as altitude increases.

A hydraulic lift works based on Pascal's principle, which states that when pressure is applied to a fluid in a confined space, the pressure is transmitted equally in all directions.

The pressure exerted by a liquid depends on its density, the depth of the liquid, and the acceleration due to gravity.

The pressure exerted by a gas is directly proportional to tempreture
The pressure exerted by a gas is directly proportional to the number of molecules of the gas. This is known as Avogadro's law.

A barometer is used to measure atmospheric pressure or the pressure of a gas.

When a person dives deep into a swimming pool, the pressure exerted by the water increases. This is because the depth of the water above the person increases, resulting in a greater weight of the water above and therefore higher pressure.

Pascal's principle states that the pressure in a fluid is transmitted equally in all directions.

The pressure exerted by a material depends on the force applied and the area over which the force is distributed. Since a block of iron is likely to have a higher force applied compared to other materials listed, it would exert the highest pressure.

A fully inflated balloon contains a higher pressure of gas compared to the surrounding air, making it an example of a high-pressure system.

The correct answer is:

               3. Pressure and temperature are directly proportional

This is based on the ideal gas law, which states that for a given amount of gas at a constant volume, the pressure of the gas is directly proportional to its temperature (in Kelvin). This relationship is often expressed as P∝T, where P is pressure and T is temperature.

According to the ideal gas law, increasing the temperature of a gas at constant volume will increase the pressure exerted by the gas.

According to Boyle's law, for a given amount of gas at a constant temperature, the pressure and volume are inversely proportional. Halving the volume while keeping the temperature constant will double the pressure, so it would be 4 atm.

The force applied can be calculated using the formula: force = pressure × area. Substituting the given values, we get force = 500 Pa × 2 m² = 1000 N.

In a fluid, pressure increases with increasing depth. This is due to the weight of the fluid above exerting a greater force at greater depths.

A flat tire has lower pressure compared to a fully inflated tire, making it an example of a low-pressure system.

According to Boyle's law, when the volume of a gas is halved at constant temperature, the pressure doubles.