Question

What happens to the power when the voltage doubles?

Answer 1

Answer:

Option D. It quadruples

Explanation:

Let the initial voltage be V.

Let the initial power be P.

We shall determine the final power of the circuit as follow:

Initial voltage (V₁) = V

Initial power (P₁) = P

Final voltage (V₂) = double the initial voltage = 2P

Final power (P₂) =?

NOTE: Resistor (R) is constant

P = V² / R

Cross multiply

PR = V²

Divide both side by P

R = V² / P

Thus

V²₁ / P₁ = V²₂ / P₂

V² / P = (2V)² / P₂

V² / P = 4V² / P₂

Cross multiply

V² × P₂ = P × 4V²

Divide both side by V²

P₂ = P × 4V² / V²

P₂ = P × 4

P₂ = 4P

Thus, the power will be four times the initial power i.e quadruple.