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 = i2 Rt.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.