When rod 1 is heated by an amount ΔT, its length increases by ΔL. If rod 2, which is twice as long as rod 1, is heated by the same amount, its length increases by how much?

## EXPERT ANSWER

let rod 1 and rod 2 are made with same materials

then change in length is directly proportional to the change in temperature

and also directly proportinal to its length

then

ΔL is directly proportional to ΔT and to L

then ΔL/(L*ΔT) = x/(2*L*ΔT)

x = 2*ΔL

So rod2 changes its length twice than the change in length of rod 1