A 40.0 ohm resistor, 20.0 ohm resistor, and a 10.0 ohm resistor are connected in series across a 220-V supply. Which resistor is the warmest? a. 40.0 ohm b. 20.0 ohm c. 10.0 ohm d. they are all the same

Answer 1

isn't Joule heating current^2 * R ?

they all have the same current...so...