(a) What do you understand by the term real image? (b) What type of mirror is used to obtain a real image? (c) Does the mirror named by your form real image for all locations? Give reason for your answer. (d) Is real image always inverted?
Answer
(a) Real image: When rays of light after reflection or refraction actually meet at some other point" the image is real. (b) Concave mirror. (c) No, this mirror does not give real image of the object that lies between principal focus and pole. (d) Yes. Real image is always ihverted.
Four uses of plane mirror are: 1. Plane mirrors are used in construction of reflecting periscope. 2. They are used as looking glass. 3. They are used in solar cookers for reflecting the rays of the sun into the cooker. 4. They are used for signalling purpose.
Why are infinite images not seen when two plane mirrors are facing each other?
Answer
Infinite images are not seen when two plane mirrors are facing each other because: 1. After every successive reflection, some amount of light energy is absorbed. Thus luminosity of image goes on decreasing, till they are no longer visible. 2. As the distance of images from the eye goes on increasing, it is unable to resolve far off images.
Laws of reflection: 1. The incident ray, the reflected ray and the normal ray at the point of incidence, lie in the same plane. 2. The angle of incidence $i$ is equal to the angle of reflection $r$ i.e. $\angle i =\angle r$.
