Question

Find the angular displacement of the hour hand of a normal clock in $4\text{h}$

• A. $\frac{\pi }{3}$
• B. $\frac{\pi }{6}$
• C. $\frac{2\pi }{3}$
• D. $\frac{3\pi }{2}$

Answer 1

The correct option is C $\frac{2\pi }{3}$

We know that,
hour hand covers $2\pi \text{rad}$ in $12\text{hrs}$


$\theta$ covered in $1\text{hr}$ $=\frac{2\pi }{12}\text{rad}$

So, $\theta$ covered in $4\text{hrs}$

$=\frac{2\pi }{12}\times 4=\frac{2\pi }{3}\text{rad}$