As shown in the figure, a parallel beam of light is incident on the upper part of a prism of angle $1.8^{\circ}$ and material of refractive index $1.5$. The light emerging from the prism falls on a concave mirror of radius of curvature $40 \,cm$. The distance of the point from the principal axis of the mirror where the light rays are focused after reflection from the mirror is:

$A$ point source is placed at a distance of $15 \, cm$ from a converging (convex) lens of focal length $10 \, cm$. At what distance (in $cm$) should a convex mirror of focal length $12 \, cm$ be placed so that the image is formed on the object itself?

In an experiment for estimating the value of focal length of a converging mirror,the image of an object placed at $40\,cm$ from the pole of the mirror is formed at a distance of $120\,cm$ from the pole of the mirror. These distances are measured with a modified scale in which there are $20$ small divisions in $1\,cm$. The value of error in the measurement of the focal length of the mirror is $1/K\,cm$. The value of $K$ is $..........$

For the refraction of light through a prism,which of the following statements is correct?

$A$ man wishing to get a picture of a Zebra photographed a white donkey after fitting a glass with black streaks onto the objective of his camera.

$A$ hemispherical glass body of radius $10\, cm$ and refractive index $1.5$ is silvered on its curved surface. $A$ small air bubble is $6\, cm$ below the flat surface inside it along the axis. The position of the image of the air bubble made by the mirror is seen: