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?
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
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