A thin rod of negligible mass, length 0.5 m and area of cross-section 4×10−6 m2, suspended vertically from one end. The rod is cooled down and it can contract by 5×10−4 m but prevented from contracting by attaching a mass at the lower end. Choose the correct option(s).
(Given: Take young's modulus of rod Y=1011 N/m2, g=10 m/s2)