Question

Give reasons:

i. Gaps are left between successive lengths of two rails

ii. Pendulum of a clock is made of invar​

Answer 1

Explanation:

i. Gaps are left between successive lengths of two rails because, during summer, the rail tracks expand and cover the gap left between the successive rails. If the gap isn't left then the rail tracks may bend due to lack of space to expand during summer.

ii. pendulum of a clock is made of invar because, Invar is an alloy which doesn't expand or contract much due to heat or cold. This the effective length of the pendulum remains unchanged which gives more accuracy of time.