$A$ ray of light passing through the principal focus of a concave mirror,after reflection,travels in which direction?

Magnification is the ratio of which of the following?

The path of a ray of light coming from air passing through a rectangular glass slab traced by four students are shown as $A, B, C$ and $D$ in the figure. Which one of them is correct?

$A$ student wants to project the image of a candle flame on a screen $60\, cm$ in front of a mirror by keeping the flame at a distance of $15\, cm$ from its pole.
$(a)$ Write the type of mirror he should use.
$(b)$ Find the linear magnification of the image produced.
$(c)$ What is the distance between the object and its image?
$(d)$ Draw a ray diagram to show the image formation in this case.

What is the wavelength range of visible light?

What type of image is formed by a plane mirror?