Question

What is the potential difference required to pass a current of 0.2 A in a wire of resistance $20\Omega$?

• A. 20 V
• B. 50 V
• C. 4 V
• D. 10 V

Answer 1

Answer: (C)

4 V

Ohm's law states that the current through a conductor between two points is directly proportional to the potential difference across the two points. Introducing the constant of proportionality, the resistance, one arrives at the usual mathematical equation that describes this relationship, I = V/R.
Rewriting this relation we arrive at $V=IR=0.2A\times 20\Omega =4V$.
Hence the potential difference required for the wire to pass current is 4 volts.