According to Ohm's law, V = IR. That is, R = V/I.

In this case, the voltage is 20 V and the current is 0.05 A.

So, the resistance R = 20/0.05 = 400 ohms.

Now, to make a current of 300 mA flow through the same resistor of 400 ohms, the potential difference to be applied is calculated as follows.

Here, I = 300 mA = 0.3 A and R = 400 ohms.

Therefore, V = 0.3*400 = 120 V.

Hence, to make a current of 300 mA flow through the same resistor of 400 ohms a potential difference of 120 V is applied.

Khushi my school friend hope you like the answer