Question

Give formula for magnification of spherical mirror.

Answer 1

Magnification is the method of increasing the apparent size, not actual size, of an object. It is the ratio of image size to the object size or ratio of image distance to object distance. A calculated number quantifies this enlargement, also called magnification. When this value is smaller than one, it reduces size, sometimes called minification or de-magnification.

Complete answer:
Spherical mirrors are mirrors having bent surfaces that are polished on one side. Convex mirrors are those spherical mirrors in which inner surfaces are painted, while the concave mirrors are those spherical mirrors in which outer surfaces are painted. Concave mirrors are known as concentrating mirrors since the rays concentrate after falling on the concave mirror, while the convex mirrors are identified as diverging mirrors as the rays deviate after falling on the convex mirror.
Magnification is the rise in the image dimension produced by spherical mirrors concerning the object size. It is the fraction of the height of the image to the object's height and is denoted as m. The magnification m presented by a spherical mirror can be shown as:
$m = \dfrac{h}{h’}$
Here, h is the height of the image, and h’ is the object's height.
Magnification is also equal to the fraction of image distance to the object distance from the mirror.
$m =\dfrac{v}{u}$
The positive magnitude of the magnification tells that a virtual and erect image is formed. The negative magnitude of the magnification tells that a real and inverted image is formed. There are some assumptions:
$1$. The distances are being estimated from the mirror pole.
$2$. According to the rule, the negative sign symbolizes the distance estimated in the direction contradiction to the incident ray while the positive sign symbolizes the distance estimated in the same direction of the incident ray.
$3$. The distance beneath the axis is negative while the distance up the axis is positive.

Additional Information:
- An exactitude magnifier obeys the function of a simple magnifier but contains multiple components to erase irregularities and yield a clearer image. A water droplet appears as a simple magnifier that amplifies the object behind it. The water makes spherical droplets due to the impact of surface tension. When the droplet is in touch with an object, a round shape is deformed but able to form an image.

Note:
- As the object is continuously above the principal axis, the height of the object is constantly positive. However, a sign for image height may change according to the nature of the image formed. The height of virtual images should be positive, while the height of actual images should be taken negatively.