The potential difference between the terminal of an electric heater is 60 V when it draws a current of 4 A from the source. What current will the heater draw if the potential difference is changed to 127.5 V?

Question

Question

This question was previously asked in

RRC Group D Previous Paper 11 (Held On: 3 Oct 2018 Shift 1)

Answer 1

CONCEPT:

Ohm’s law: At constant temperature and other physical quantities, the potential difference across a current-carrying wire is directly proportional to the current flowing through it.

V= R I

Where V is the potential difference, R is resistance and I is current

CALCULATION:

Given that:

In first instance, V = 60 volts, I = 4 Ampere

Therefore, Resistance (R) = V/I = 60/4 = 15 Ohms

In second instance, V = 127.5 Volts and R (as calculated above) = 15 Ohms.

Therefore, Current (I) = V/R = 127.5/15 = 8.5 Ampere.

Thus, the heater will draw a current of 8.5 Ampere, if the potential difference is changed to 127.5 V. So option 1 is correct.