A small bulb is placed at the bottom of a tank containing water to a depth of √ 7 m. The refractive index of water is 4/3. The area of the surface of…

A small bulb is placed at the bottom of a tank containing water to a depth of $\displaystyle \sqrt{7} m$. The refractive index of water is $\displaystyle \frac{4}{3}$. The area of the surface of water through which light from the bulb can emerge out is $\displaystyle x \pi m^2$. The value of $\displaystyle x$ is \_\_\_\_.