Question

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

• A. 2W
• B. 4W
• C. 6W
• D. 8W

Answer 1

The correct option is C

6W

Power is defined as the work done per unit time.
The heart beats 72 times in one minute so, in one second it would beat $\frac{72}{60}$times and in one beat it consumes an energy of 5J, so in $\frac{72}{60}$ times it would consume $\frac{72}{60}$ × 5 = 6 J and 6 J is also the energy consumed in one second.
Hence, Power = 6 W.