Properties of matter questions | form five Physics

The surface tension of a fluid is due to

1. molecules on its surface
2. a semi-permeable membrane which covers it
3. The brownian motion of surface molecules
4. the adhesive force between molecules of different materials

Briefly explain the following observations:
(i) The rise of the liquid is affected if the top of the capillary tube is closed.
(ii) Rain drops are spherical in shape.

Why brick walls are plastered with cement?

A barometer contains two uniform capillary tubes of radii 6.5×10^-4m and 1.24×10^-3m. If the height of water in a narrow tube is 0.2 m more than that in the wide tube, calculate the true pressure difference.

What is meant by surface tension? Give its S.I. units.

During the rain, 64 rain drops combined into a single drop. Calculate the ratio of the total surface energy of the 64 drops to that of a single drop.

Define Young`s Modulus of a material.

Why work is said to be done in stretching a wire?

A steel wire AB of the length 60cm and cross sectional area 1.5x10^-6 m² is attached at B to copper wire BC of length 39cm and cross sectional area 3.0x10^-6m². If the combination of the two wires is suspended vertically from a fixed point at A, and supports a weight of 250N at C; find the extension (in millimeter) of the

1. Steel wire
2. Copper wire

Based on the kinetic theory of gases determine

1. The average translational kinetic energy of air at a temperature of 290K.
2. The root mean square seed (r.m.s) of air at the same temperature as in (i).