Question

A 500 watt heater carries a current of 4 A. What is the resistance of the heating element?Group of answer choices85.7 Ω42.8 Ω31.3 Ω11.2 Ω

Answer 1

ANSWER

31.3 Ω

EXPLANATION

Given:

• The power of the heating device, P = 500 W

,

• The current, I = 4 A

Unknown:

• The resistance of the heating device, R

The power, P, on a resistance R when a current I flows through it is,

$P=I^2\cdot R$

Solving for R,

$R=\frac{P}{I^2}$

Replace with the known values,

$R=\frac{500W}{4^2A^2}=31.25\Omega\approx31.3\Omega$

Hence, the resistance of the heating device is 31.3 Ω.