Looking into a mirror one finds his image long and thin; the mirror is:
A. Concave
B. Convex
C. Cylindrical
D. Parabolic

Hint: Images that are turned upside down and images that are not inverted can both be produced by a cylindrical mirror. The image you see in a cylindrical mirror is determined by the mirror's orientation and the distance between you and it.


Complete step-by-step solution:
In a Cylindrical Mirror, one finds his image long and thin.
These mirrors are ideal for use with ray boxes to measure mirror focal lengths and demonstrate cylindrical aberration (analogous to spherical aberration).
A cylindrical mirror, unlike a spherical mirror, concentrates light into a line rather than a point. A cylindrical mirror's curved face or faces are parts of a cylinder that concentrate the image passing through them into a line parallel to the intersection of the lens's surface and a plane tangent to it.
A concave spherical mirror magnifies the dentist's view of the mouth while still refracting a small amount of light. This means the picture in the mirror is bigger, sharper, and easier to see for the dentist.
Since they are curved outwards, convex spherical mirrors have a very wide field of view. As a result, compared to a plane mirror, convex mirrors allow the driver to see a much larger area. The photographs that are created are upright and much smaller than the object.

Note: In cases where the spherical aberration of a standard spherical mirror will be a serious concern, parabolic mirrors are used. Radio telescopes receiving dishes are usually parabolic. They reflect incoming radio waves from (extremely) faraway astronomical sources, bringing them to a single point where a detector is mounted. A spherical mirror is one that is shaped like a piece cut from a spherical surface. Concave and convex spherical mirrors are the two types of spherical mirrors. Shaving mirrors and makeup mirrors are two of the most common types of concave mirrors.