Class 10 Light & reflections

An object is at a distance of 0.5 m in front of a plane mirror. Distance between the object and image is

• 0.5 m

• 1 m

• 0.25 m

• 1.5 m

Number of images formed when two plane mirrors are inclined at an angle 90° is

• 3

• 2

• 4

• 5

Which one of the following statements is not correct?

• A convex mirror is often used as driving rear-view mirror.

• A convex mirror is often used as a shaving mirror.

• A concave mirror is often used in a search light or a torch.

• A concave mirror is often used as the reflector behind lamp in a projector

The relation, R = 2f holds true for :

• concave mirrors only

• convex mirrors only

• all spherical mirrors

• lens as well as for all spherical mirrors.

A magnification greater than unity indicates :

• real image

• size of the image is smaller than that of object

• size of the object is smaller than that of image

• size of object is equal to that of image

The image formed by a convex mirror

• is always real

• is always virtual

• cannot say

• None of these

In case of erect object having inverted image, linear magnification is :

• positive

• negative

• zero

• no definite sign.

If object lies symmetrically and number of images formed are 9, therefore two plane mirrors are kept at an angle of :

• 72°

• 40°

• 36°

• 50°

Reciprocal of focal length of a lens gives the

Magnification of a lens is given by