The heat developed can be calculated using the power rules as follows:
P = I x V = I^2 x R
First solution is to use the given values of I and R as follows:
P = I^2 x R = (2)^2 x 25 = 4 x 25 = 100 watt
Second solution is to use ohm's law to get V, then substitute to get the power as follows:
V = I x R = 2 x 25 = 50 volts
Power = V x I = 50 x 2 = 100 watt
