Physics - Geometrical Optics Question with Solution | TestHub

As we know, if a mirror is rotated.

Given, angular acceleration,$\alpha =\mathrm{\pi }\text{r}\text{a}\text{d}/{\text{s}}^2$

Initial angular velocity$={\omega }_0=0$

Time,$t=\frac{1}{4}\text{ s}$

Now, as$\theta ={\omega }_{0}t+\frac{1}{2}\alpha t^2$

$=0\times \frac{1}{4}+\frac{1}{2}\times \pi \times {\left(\frac{1}{4}\right)}^2$

$=\frac{180}{2\times 16}={5.625}^{\text{o}}$

Since, mirror is turned by${5.625}^{\text{o}}$, therefore reflected ray will be turned by$2\times 5.625={11.25}^{\text{o}}$.

Hence, option$\left(\text{4}\right)$is correct.