In a slide projector, light from a lamp is incident on to a slide $MN$ and a lens is used to form an image of the slide on a screen as shown in figure. What kind of image is formed on the screen?

Read the given statements and select the correct option.

Statement 1: Even when one half of a convex lens is covered with a black paper, the lens will produce a complete image.
Statement 2: Intensity of image is reduced when we cover the half of a convex lens with a black paper.

In the following figures, optical instruments are placed inside boxes (a) and (b). Which of the following options is correct for these?

Read the passage carefully and answer the following questions.

The path of a light ray from air to two different media $A$ and $B$ for a given angle of incidence is as shown.

If $n_A$ and $n_B$ are the refractive indices of two media, then:

Read the passage carefully and answer the following questions.
The path of a light ray from air to two different media $A$ and $B$ for a given angle of incidence is as shown.

In the given diagram, three rays of light pass through focal point $F_1$ to the converging lens, placed along vertical line. Which of the following is correct regarding this?

A ray of light passing through a semicircular block (a denser medium) from air is shown below. Consider the given figure and select the correct option which correctly identifies the true (T) and false (F)?

(i) There is no change in the direction of ray at $P$ because light ray incident on semicircular block at $90°$.
(ii) As light rays enters the semicircular block, its frequency remains the same.
(iii) Wavelength of light rays as it enters the block decreases.
(iv) Speed of light as it enters the block increases.

A man standing at a position $X$ in front of a plane mirror, at a distance of $y$ metre from the mirror as shown in figure. When the man moves $5 \mathrm{m}$ away from the mirror, the new distance between the man and his image becomes $20$ metre. What is the value of $y$?

To produce an image by a convex lens, at the position shown (see figure) the object is needed to be placed: