Question

A uniform metal rod of 2 mm2 cross-section is
heated from 0°C to 20°C. The coefficient of the
linear expansion of the rod is 12 x 10-6/°C. Its
Young's modulus of elasticity is 1011 N m-2. The
energy stored per unit volume of the rod is
(1) 1440 J m 3
(2) 15750 J m 3
(3) 1500 J m-3
(4) 2880 J m-3​

Answer 1

An15750 jm3

Explanation:

Answer 2

Answer:

2880 J m³

Explanation: We know that

Energy = 1/2 × stress × strain × volume

∴ Energy / volume = 1/2 × stress × strain

                              we also know that stress = Y × strain  ( Y = youngs modulus of elasticity)

and strain = αΔT

Energy / volume = 1/2 × Y × (αΔT)²

                         = 2880 J / m³