Calculate the resistance of the filament of a lamp rates 240V; 40W?

A. 240Ω
B. 360Ω
C. 720Ω
D. 1440Ω
E. 2880Ω

Correct Answer:

Option D – 1440Ω

Explanation

R = V²/P = 240²/40 = 1440Ω