What is the minimum size of mirror required for a $6\mathrm{ft}$ tall person to be able to see a full length image?

Letters $A,B,C$ and $D$ are written on a cardboard as shown in the figure below.

The cardboard is kept at a suitable distance behind a transparent empty glass of cylindrical shape. If the glass is now filled with water, one sees an inverted image of the pattern on the cardboard when looking through the glass. Ignoring magnification effects, the image would appear as

A mirror is placed at an angled of $30°$ with respect to $y-$axis (see figure). A light ray travelling in the negative $y-$direction strikes the mirror. The direction of the reflected ray is given by the vector

The refractive index of the material of the prism and liquid are $1.56$ and $1.32$, respectively. What will be the value of $\theta$ for the following refraction?