Question

Two resistors of equal resistances are joined in series and a current is passed through the combination. Neglect any variation in resistance as the temperature changes. In a given time interval,

(a) equal amounts of thermal energy must be produced in the resistors

(b) unequal amounts of thermal energy may be produced

(c) the temperature must rise equally in the resistors

(d) the temperature may rise equally in the resistors

Answer 1

(a) equal amounts of thermal energy must be produced in the resistors

(d) the temperature may rise equally in the resistors

 

In a resistor of resistance R, current i is passed for time t then the thermal energy produced in the resistor will be given by

H = i²Rt.

As the resistors are in series, the current through them will be same. Thus, the amount of thermal energy produced in the resistors is same. The rise in the temperature of the resistance will depend on the shape and size of the resistor. Thus, the rise in the temperature of the two resistances may be equal.