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

When a plane mirror is rotated by an angle $\theta$,the reflected ray turns by an angle $2\theta$. Is this statement true or false?

What is meant by the radius of curvature of a spherical mirror? How is it related to the focal length of the mirror?

When an object is placed beyond the center of curvature $(C)$ in front of a concave mirror,where is the image formed and what is its nature?

How many images are formed by two parallel mirrors?

$(a)$ Define radius of curvature and focal length of a spherical mirror and show it on a figure.
$(b)$ Write the relation between the radius of curvature and the focal length of a spherical mirror.