Force, Work, Power and Energy — Physics STD 10 — Question

In which one of the following cases is the work done more? When the angle between the direction of motion and that of the force is (i) 90° (ii) 0°.

An electric kettle is rated 3kW, 250V. What should be the current capacity of the fuse with it?

A cell is used to send current to an external circuit. (a) How does the voltage across its terminals compare with its e.m.f? (b) under what condition is the e.m.f of a cell equal to its terminal
voltage?

When a body moves in a circular path, how much work is done by the body? Give reason.

The refractive index of water with respect to air is a μ w and of glass with respect to air is a μ g.
express the refractive index of glass with respect to water.

In an experiment. 17 g of ice is used to bring down the temp. of 40 g of water from 34°C to its freezing point. The sp. heat capacity of water is 4.25 J/g°C. Calculate sp. latent heat of ice.

(a) Name the radioactive radiations which have the least penetrating power.
(b) Give one use of radio isotopes.
(c) What is meant by background radiation?

How do you account for the fact that two strings can be used to give notes of the same pitch and loudness but of different quality?