The power consumption of an electrical device varies directly with the square of the voltage applied. If a device consumes 150 watts when the voltage is 120 volts, how much power (in watts) will it consume at 240 volts?
Show answer & explanation
Correct answer: D
Explanation
The correct answer is option 4 i.e. 600.
Power ∝ Voltage2
⇒ P1 / P2 = V12 / V22
⇒ 150 / P2 = 1202 / 2402
⇒ 150 / P2 = 14400 / 57600
⇒ 150 / P2 = 1 / 4
⇒ P2 = 150 × 4 = 600