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 current will the heater draw if the potential difference is increased to 120 V?​

Answer 1

⟶ Given :-

Potential energy, V = 60V.

Current, I = 4A.

⟶ To find :-

The current through the heater.

⟶ Solution :-

According to ohm law,

.i.e.,

$\sf R = \dfrac{V}{I} = \dfrac{60}{4} = 15 \Omega$

When the potential difference is increased to 120V.

The current is given by,

$\sf current = \dfrac{V}{R} = \dfrac{120}{15 \Omega} = 8A$

Thus, the current through the heater becomes 8A.

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.