Question

A North American tourist takes his 26.0 W, 120 V AC razor to Europe, finds a special adapter, and plugs it into 220 V AC. Assuming constant resistance, what power in watts does the razor consume as it is ruined?

Answer 1

Explanation:

For North America,

Power, P = 26 W

Voltage of AC razor, V = 120 V

For Europe,

Voltage of AC razor, V' = 220 V

The power of razor in North America is given by :

$P=\dfrac{V^2}{R}\\\\R=\dfrac{V^2}{P}\\\\R=\dfrac{120^2}{26}\\\\R=553.84\ \Omega$

Let P' is the power consumed by razor in Europe. Now,

$P'=\dfrac{V'^2}{R}\\P'=\dfrac{220^2}{553.84}\\\\P'=87.38\ \Omega$

So, the razor consumed 87.38 watts of power as it is ruined.