An air bubble in a glass slab $(\mu = 1.5)$ appears to be $5 \, cm$ deep when viewed through one face and $2 \, cm$ deep when viewed through the opposite face. What is the thickness of the slab in $cm$?

$A$ container is filled with a liquid of refractive index $\mu_1$ up to a depth $d$ and another liquid of refractive index $\mu_2$ up to a depth $d$ is poured on top of it. What is the apparent depth of the container when viewed from above?

If the velocity of light in vacuum is $3 \times 10^{8} \text{ m/s}$,the time taken (in nanoseconds) to travel through a glass plate of thickness $10 \text{ cm}$ and refractive index $1.5$ is:

$A$ vessel of depth $x$ is half filled with oil of refractive index $\mu_1$ and the other half is filled with water of refractive index $\mu_2$. The apparent depth of the vessel when viewed from above is

$A$ printed page is kept pressed by a transparent cube of edge $t$. The refractive index of the cube varies as $\mu(z) = 1 + \frac{z}{t}$,where $z$ is the vertical distance from the bottom of the cube. If viewed from the top,then the printed letters appear to be shifted by an amount

The image of point $P$ when viewed from the top of the slabs will be: