You buy a light bulb in the U. S. labeled 75 watts. Since you bought it in the U. S., the power rating assumes that the potential difference across the light bulb will be 120 volts. Instead, you provide it with a potential difference of 220 volts (the potential difference provided by wall outlets in most European countries). Will the light bulb dissipate 75 watts of power?

    P₂ = 252 W

Explanation:

The electrical power is

          P = V I

The potential difference is

         V = I R

         I = V / R

Let's replace

        P = V² / R

Let's use the given values to calculate the resistance of the bulb

         R = V² / P

         R = 120²/75

         R = 192 ohm

This resistance value does not depend on the applied voltage, so it is constant

Let's calculate the power in Europe

        P₂ = V₂² / R

       P₂ = 220²/192

       P₂ = 252 W

the bulb dissipates much more power