Subject :Physics Class : Class 7
Case study :All solids are found to expand on heating
and contracts on cooling . This is called thermal
expansion.
Thermal expansion is the tendency of matter to
change in shape, area and volume in response to a
change in temperature. When a solid is heated, its
atom vibrate faster about their fixed points. Metallic
railway tracks have small gaps so that when the sun
heats them, the tracks expand into these gaps and
don't buckle.
From the given figure, conclude the correct
option from the following.
A The solids contract on heating.
B Before heating, when the ball is kept on the
ring it just slips through the ring.
C Solids expand on cooling.
D All of the above.