The scale of a galvanometer is divided into 160 equal divisions. The galvanometer shows full scale deflection of 16 mA and maximum voltage is 80 mV . Now the range is changed so that galvanometer reads 160 V . The required resistance to be connected is

Step-by-step solution

Converting a galvanometer to a voltmeter requires connecting a high resistance in series with the galvanometer. The galvanometer resistance is calculated from its full-scale deflection voltage and current: V_g = 80 10⁻³ V and I_g = 16 10⁻³ A. By Ohm's law, R_g = V_g / I_g = 5 . To extend the voltage range to 160 V, the total voltage is given by V = I_g (R_g + R_s) , yielding 160 = 16 10⁻³ (5 + R_s) . Solving for R_s gives R_s = 9995 . The required series resistance is A .