Which of the following statements is true regarding a real image of an object?

$A$ ray of light $XY$ is incident on a spherical mirror as shown in the diagram. Redraw the diagram and mark the normal,angle of incidence and angle of reflection.

For the same angle of incidence in media $P, Q$ and $R$,the angles of refraction are $45^{\circ}, 35^{\circ}$ and $15^{\circ}$ respectively. In which medium will the velocity of light be minimum? Give reason.

What is the nature of the final image formed by an astronomical telescope compared to the object?

When a plane mirror is rotated through a certain angle,the reflected ray turns through twice as much and the size of the image

Both a spherical mirror and a thin spherical lens have a focal length of $-15 \; cm$. What type of mirror and lens are they?