If 'α' is coefficient of thermal expansion, 'ΔT' is magnitude of change in temperature and 'E' is modulus of elasticity, then the expression for thermal stress induced in a rod of length 'l' that is fixed between two rigid ends is given as-

• A. αElΔT
• B. αEΔT
• C. αΔT/El
• D. αlΔT