Question

How much energy is consumed when a current of 1 amperes flows through the filament of a heater having resistance of 100 ohms for two hours? Express it in joules

Answer 1

Energy =
${i}^{2} \times r \times t$
So, i = 1 A
r = 100 ohms.
t = 2 hours = 7200 seconds.

So, Energy =
${1}^{2} \times 100 \ \times 7200 \: = 7.2 \: \times {10}^{5} joules.$