Question

Name the type of mirror used as a shaving mirror-
(a). Concave mirror
(b). Convex mirror
(c). Plane mirror
(d). None of the above

Answer 1

- Hint: Study the nature of images formed by a plane mirror keeping the object at different positions. Also, study the nature of images formed by the two spherical mirrors namely convex mirror and concave mirror when the object is placed at different positions. Then find the nature of the image required in the shaving mirror and compare it with the images formed by different mirrors.

Complete step-by-step solution -

Concave mirror- Images formed by Concave mirrors are real and inverted. If the object is placed at infinity or beyond the center of curvature then the size of the image is smaller than that of the object. If the object is placed at the center of curvature then the image is of the same size. And if the object is placed between the center of curvature and focus, the size of the image is larger than that of the object. In special cases, that is when the object is placed between pole and focus, an image formed by the concave mirror is virtual, erect, and enlarged.

Convex mirror- Images formed by convex mirrors are virtual, erect, and diminished for an object placed anywhere between pole and infinity or at infinity.

Plane mirror- Image formed by a plane mirror is always virtual, erect, and of the same size as the object.

The shaving mirrors are used to view the enlarged image of the face. To view the enlarged image of the face we should use concave mirrors because they form a virtual, erect, and enlarged image when an object is placed near the mirror (between pole and focus).

Additional Information:
Concave mirrors can also be used as/in :
Makeup mirrors,
Reflecting telescopes.
Torchlight
Headlight

Convex mirrors can be used as/in:
Rear side mirrors in vehicles
Magnifying glass
Street light reflectors
Sunglasses

Plane mirrors are used as/in:
Dressing tables
Periscopes and kaleidoscopes
Solar cooker
Looking Glasses

Note: In the case of a plane mirror, the image formed is virtual, erect, and of the same size as that of the object. In case of a convex mirror, the image formed is virtual, erect, and diminished. Thus, in both cases, magnified images will not be observed.
To understand the images formed by mirrors when an object is placed at different positions, ray diagrams can be formed. They give a better and clear understanding.