Question

 How much heat will an instrument of 12 W produce in one minute if it is connected to the heat produced by it?  

Answer 1

 Given: Power rating (P) = 12 W
Time interval (t) = 1 minute = 60 s                              (1 minute = 60 seconds)
Potential difference (V) = 12 V
Heat = I²Rt
But, we know that P = I²R
Therefore, H = P x t = 12 W x 60 s = 720 joules