# A railway track (made of iron) is laid in winter when the average temperature is 18°C. The track consists of sections of 12"0 m placed one after the other. How much gap should be left between two such sections so that there is no compression during summer when the maximum temperature goes to 48°C ? Coefficient of linear expansion of iron = 11 x 10 6/°C.

• Gap between two tracks=2l-2l0=2l0+2l0($\Delta \alpha$​)$\Delta$t -2l0=2*11*10-6*(48-18)=7.92*10-4m