The active element of a certain laser is an ordinary glass rod 25 cm long and 1.0 cm in diameter...?

Question

The active element of a certain laser is an ordinary glass rod 25 cm long and 1.0 cm in diameter. If the temperature of the rod increases by 73°C.
(a) Find its increase in length.

(b) Find its increase in diameter.

(c) Find its increase in volume.

Answer 1

The coefficient of thermal expansion for glass is about 9 x 10 ^ -6 1/degrees C.

(a) The increase in length is found by the equation

Change in Length = Length * coefficient of linear expansion * change in temperature

(b) and (c) are similar. The coefficient of area expansion is the linear coefficient squared, and the coefficient of volume expansion is the linear coefficient cubed.