An electric iron is rated 1000W; 230V. What is the resistance of its elements?

A. 51.9Ω
B. 52.9Ω
C. 55.9Ω
D. 57.6Ω

Correct Answer:

Option B = 52.9Ω

Explanation

Electric Power = IV = I²R = ^V2/_R thus for a device rated 1000 W, 230V, from the relation P = ^V2/_R, 1000 = ⁽²³⁰⁾²/_R
=> R = ⁽²³⁰⁾²/₁₀₀₀
= 52900/1000 = 52.9Ω