Question

The potential difference between the terminals of an electric heater is 60 V when it draws a current of 4 A from the source. What is current drawn by the heater if the potential difference is increased by 120 V?

Answer 1

Answer:

v=60

I=4A

v=IR

R=60/4=15

so resistance is constant in the circuit

V=120

I=?

R=15

I=V/R

I=120/15=8A

so the current drawn by the heater when V is 120v is 8

ampere

Answer 2

Answer:

The current through the heater becomes 8 A.

Explanation:

Given,

The potential difference between the terminals of an electric heater is 60 V.

Current of 4 A is drawn from the source.

To find: What current will the heater draw if the potential difference is increased to 120 V

Solution:

According to Ohm's law, Potential difference is directly proportional to current.

i.e V  $\propto$  I

or, V = iR

here, V = 60 V and i = 4 A

Substituting the values,

R = V / i = 60 / 4 = 15 Ω

Now, V is increased to 120 V.

Again using ohm's law,

i = V / R = 120 / 15 =  8 A

Therefore, The current through the heater becomes 8 A.