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

We wish to obtain an erect image of an object,using a concave mirror of focal length $15\, cm$. What should be the range of distance of the object from the mirror? What is the nature of the image? Is the image larger or smaller than the object? Draw a ray diagram to show the image formation in this case.

The radius of curvature of a spherical mirror is half of the focal length.

The mirror outside the driver's side of a vehicle is usually a convex mirror. Printed on such a mirror is usually the warning "Vehicles in this mirror are closer than they appear". What is the reason for this warning?

Name the spherical mirror used as:
$(a)$ $1.$ Shaving mirror,
$2.$ Rear-view mirror in vehicles,
$3.$ Reflector in searchlights.
$(b)$ Write any three differences between a real and virtual image.

Define the term principal focus for a convex mirror.