Question

The potential difference between the terminals of an electric heater is 60v when it draws a current of 4 A from the source. what current will the heater draw if the potential difference is in increased to 12V?
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Answer 1

Answer:

The potential difference between the terminals of an electric heater is 60v when it draws a current of 4 A from the source. If the potential is increased to 120 V, The current becomes 8A.  

Explanation:

Given,

Potential difference , V = 60 V

Current drawn from the source, A = 4A

From Ohm's law,

V = RI   where R is the resistance.

Substituting values of V and I to the above equation.

$\mathrm{R}=\frac{\mathrm{V}}{\mathrm{I}}=\frac{60}{4}=15 \Omega$

If the potential difference is increased to 120V,  the current becomes

$\mathrm{I}=\frac{\mathrm{V}}{\mathrm{R}}=\frac{120}{15}=8 \mathrm{~A}$