A long, narrow steel rod of length 2.5000 m at 25 C is oscillating as a pendulum about a horizontal axis throu?

A long, narrow steel rod of length 2.5000 m at 25 C is oscillating as a pendulum about a horizontal axis through one end. If the temperature changes to 0 C, what will be the fractional change in its period? (For the value of coefficient of linear thermal expansion of steel use 12x10^6 C^-1.)