Question

A bulb is connected to a battery of potential difference 4 V and internal resistance 2.5 $\Omega$. A steady current of 0.5 A flows through the circuit. The total energy supplied by the battery in 10 minutes is :

• A. $120J$
• B. $600J$
• C. $1200J$
• D. $300J$

Answer 1

The correct option is C $1200J$

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 $VI\times tasP=VI$.

In the question, it is given that the current I is 0.5 A, voltage V is 4 V and the time taken is 10 minute, that is, $10\times 60=600seconds$. The heated generated is given as $Q=VI\times t$.

Hence, the total energy supplied by the battery in 10 minutes is $0.5A\times 4V\times 600s=1200Joules$.