Question

Each time the heart beats, it requires $5J$ of energy. If it beats 72 times in one minute, then the power consumed by the heart is:

• A. $3W$
• B. $6W$
• C. $3W$
• D. $12W$

Answer 1

The correct option is B $6W$

Given: energy required per beat $=5J$, number of beats $=72$, and time, $t=2mins=120s$
Let the power consumed by the heart be $P$.

Energy required by the heart in one minute $=72\times 5=360J$

Power, $P=\frac{\text{energy}}{\text{time}}$
$\Rightarrow P=\frac{360}{60}=6W$
Therefore, the power consumed by the heart is $6W$.