Question

A "590-w" electric heater is designed to operate from 120-v lines. what is its operating resistance?

Answer 1

24.4 Ω

Step-by-step explanation:

Thinking process:

The equation relating the power and voltage is given as:

`R = (V^(2) )/(P)`

Given that:

Power = 590 W

Voltage = 120 V

The power therefore will be:

`P = ((120)^(2) )/(590)`

= 24.4 Ω

Answer 2

The power used by an electrical device can be written as

`P= (V^2)/(R)`
where V is the potential difference applied to the device and R is the electrical resistance of the device.

In this problem, the power used is P=590 W and the device operates at voltage of V=120 V, therefore we can re-arrange the previous equation to calculate its resistance:

`R= (V^2)/(P)= ((120V)^2)/(590 W)= 24.4 \Omega`