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

Resistance = Voltage/Current
Wattage = Voltage * Current

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

Resistance =
`(210)/( (100)/(210) )`

Answer 2

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=(V^2)/(R)`

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

`R=((210\ V)^2)/(100\ W)`

R = 441 ohms

So, the resistance of the lamp is 441 ohms

Hence, this is the required solution.