Question 7
Iron rim is made slightly smaller than the wooden wheel. The rim is usually heated before fixing into the wooden wheel because on heating the iron rim
(a) expands and fits onto the wooden wheel
(b) contracts and fits onto the wooden wheel
(c) no change in the size take place
(d) expands first, then on cooling contracts and fits onto the wooden wheel
On heating, the iron rim, which is a metal expands. On cooling, it contracts and fits onto the wooden wheel.
Expansion occurs on heating whereas contraction occurs on cooling. So, option (d) is the correct answer.