Numerical from the chapter "Expansion of solids"

[riwaj]

A rod is measured to be 20.05cm long using a steel ruler at a room temperature of 20*C. Both the rod and the ruler are placed in an oven at 270*C where the rod now measures 20.11 cm using the same ruler. Calculate the coefficient of thermal expansion for the material of which the rod is made. [Given: coefficient of linear expansion of the material of the scale=11x10^(-6) per *C]

[jake-the-peg]

You need to calculate how much the steel ruler will expand - you can do this because you have the coefficient of expansivity of the ruler.

Knowing that, you know what 20.11 cm would measure at 20 degrees

Now you know the length of the rod at 20 degrees and at 270 degrees so you can calculate the coefficient.

I'm sure your text book will have examples of each of these steps.

(PS you will also tend to get more help if you 'talk' to people on here rather than just typing in your homework question parrot style - which tends to make people think you're just being lazy whether or not that is the case)