Question

A sonometer wire having cross sectional area 0.85×1/1000000 m2 is stretched between two rigid supports 1.2 my apart .A tension of 20 N is applied at its free end .if the temperature is reduced by 12°C, Calculate the field tension in the wire .Take coefficient of linear expansion & isothermal young's modulus to be 1.5× 1/100000 1/K & 2 ×100000000000 N/my, respectively.