JEE Mains 28-July-2022 Shift 1 Solved Paper

As shown in the figure, a potentiometer wire of resistance 20Ω and length 300‌cm is connected with resistance box (R.B.) and a standard cell of emf 4 V. For a resistance ' R ' of resistance box introduced into the circuit, the null point for a cell of 20‌mV is found to be 60‌cm. The value of ' R ' _______ is Ω.