Question

If the heart pushes $1\mathrm{cc}$ of blood in $1\mathrm{s}$ under pressure $20000{\mathrm{Nm}}^{-2},$ the power of the heart is

• A. $0.02\mathrm{W}$
• B. $400\mathrm{W}$
• C. $5\times {10}^{-10}\mathrm{W}$
• D. $0.2\mathrm{W}$

Answer 1

The correct option is A

$0.02\mathrm{W}$

Step 1 Given data

Pressure, $\mathrm{P}$ is $20000{\mathrm{Nm}}^{-2}$

Volume per second is $1\mathrm{cc}$

Here, $1\mathrm{cc}={10}^{-6}\mathrm{L}$

Step 2 Formula used

$\mathrm{Power}=\mathrm{Pressure}\mathrm{x}\mathrm{volume}\mathrm{per}\mathrm{second}$

Step 3 Power of heart

The heart pushes $1\mathrm{cc}$ of blood in $1\mathrm{s}$ under pressure $20000{\mathrm{Nm}}^{-2}$,

That is,

$$\begin{gathered} \mathrm{Power}\mathrm{of}\mathrm{heart}=\mathrm{Pressure}\mathrm{x}\mathrm{volume}\mathrm{per}\mathrm{second} \\ \mathrm{Power}\mathrm{of}\mathrm{heart}=20000\times {10}^{-6} \\ \mathrm{Power}\mathrm{of}\mathrm{heart}=0.02\mathrm{W} \end{gathered}$$

The power of the heart is $0.02\mathrm{W}$. Hence, option A is correct.