Question

The filament of a 240 V, 100 W electric lamp heats up from room temperature to its operating
temperature. As it heats up, its resistance increases by a factor of 16.
What is the resistance of this lamp at room temperature?
A 36Ω B 580Ω C 1.5 kΩ D 9.2 kΩ

Answer 1

P=VI
What is I? P= power (Watts), V = volts (V)

Answer 2

P=VI
P=V^2 /R

Answer 3

why to calculate I?

Answer 4

V=IR
What is R?

Then find the resistance at room temperature
Divide R by 16

Answer 5

So, u got 36?

Answer 6

yes

Answer 7

But I am confused by the word factor 16