Question

A lamp that uses 100.0 watts of power requires a voltage of 210.0 volts. What is the resistance of the lamp?

Answer 1

Answer:

R = 441 ohms

Explanation :

It is given that,

Power of the lamp, P = 100 watts

Voltage, V = 210 volts

The power of an electrical appliance can be written as :

$P=\dfrac{V^2}{R}$

$R=\dfrac{V^2}{P}$

$R=\dfrac{(210\ V)^2}{100\ W}$

R = 441 ohms

So, the resistance of the lamp is 441 ohms

Hence, this is the required solution.

Answer 2

Resistance = Voltage/Current
Wattage = Voltage * Current

That means the current drawn by the lamp is equal to 100 watts divided by 210 volts.

Resistance =$\frac{210}{ \frac{100}{210} }$