The image formed by a lens is due to which optical phenomenon?

If a convex lens forms a real and magnified image of an object,where is the object placed?

What is the radius of curvature of a plane mirror?

$A$ girl was playing with a thin beam of light from her laser torch by directing it from different directions on a convex lens held vertically. She was surprised to see that in a particular direction the beam of light continues to move along the same direction after passing through the lens. State the reason for this observation.

The magnification of a mirror is $+1$. What does it mean?

What is the point,where the rays parallel to the principal axis meet after reflection,called?