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Physics

Definitions for Chapter (2)

1. Pressure

The normal forces per unit area is called pressure.

2. Barometer

Barometer is a device for measuring atmospheric pressure.

3. Atmospheric pressure

The pressure exerted by the atmospheric on all living and non-living things on earth is called

atmospheric pressure.

4. Manometer

A glass tube open at both ends and bent into a U-shape, serves as a sensitive device for

measuring pressure when filled with coloured water or light oil. Such a device is called manometer.

5. Buoyancy

When bodies are immersed in a liquid, there is loss in weight. This is because of a property of

liquids called buoyancy.

6. Archimedes’ principle

The upward thrust acting on a body which is immersed in a liquid is equal to the weight of

the liquid displaced by the body.

7. Pascal’s law

When a fluid completely fills a vessel and a pressure is applied to it at any part of the surface

that pressure is transmitted equally throughout the whole of the enclosed fluid.

8. One Pascal

If the normal force on 1m2 is 1N, the pressure is 1pascal.

9. Density

Density is defined as the ratio of its mass to volume.

10. Hygrometer

The hygrometer is an instrument for measuring the density or relative density of liquids.