Question

The length of a minute hand of a clock is $7cm.$ Area swept by it in $30$ minutes be$:$

• A. $66c{m}^2$
• B. $77c{m}^2$
• C. $88c{m}^2$
• D. None of these

Answer 1

The correct option is B

$77c{m}^2$

It is given that length of a minute hand of a clock is $7cm.$

We want to find out area swept by it in $30$ minutes

Area swept by minute hand of a colck $=\frac{1}{2}\times \mathrm{\pi }{\mathrm{r}}^2$

$=\frac{1}{2}\times \frac{22}{7}\times 7\times 7$

$=11\times 7$

$=77c{m}^2$

Hence$,$ the area swept by minute hand of clock in $30$ minutes is $77c{m}^2$, therefore option $B$ is correct