Question

An electric current of 2.0 A passes through a wire of resistance 25 $\Omega$. How much heat (in joule) will be developed in 1 minute?

• A. 6
• B. 6000
• C. 50
• D. 10

Answer 1

Answer: (B)

Energy ($power\times time$) is measured in Joules and by including time (t) in the power formulae, the energy dissipated by a component or circuit can be calculated.
Energy dissipated = Pt or $VI\times tasP=VI$.
It can also be written as $I^2\times RtasV=IR.$
Hence, the expression for Power in terms of current is given as $P=I^{2}RtJ$.
It is given that resistance is 25 ohms and current is 2.0 A. The time taken is 1 minute, that is $1\times 60=60seconds$.
Therefore, $P=2^2\times 25\times 60J=6000J$.
Hence, the heat energy developed by the electrical appliance in 1 minute is 6000 J.