A metal meter scale gives correct measurement at  400C  it is generally used at a temperature of 00C . Find the correction to be made for every meter  α=10−6/0C

change in length is Δl=lαΔt  l is initial length of rod =1m;α is coefficient of linear expansion=10-6/C  0 Δt  is change in temperatue; decreased from 400C to 00C Δl=1×10−6×40 Δl=4×10−5mIf t2