Chhattisgarh State Board Class 8 Science Chapter 9 Refraction of Light Exercise Multiple Choice, Matching , Questions and Answers here.
Choose the correct alternatives
1.) The refractive index of glass is –
Ans- a) 1.5
2) The point from which a light ray passes without any deviation is the –
b) Optical centre
c) Focal length
d) Centre of curvature
Ans-b) optical centre
3.) When light passes from one medium to another , it deviates from its path .this is called-
a) Reflection of light
b) Irregular reflection of light
c) Refraction of light
d) None of these
Ans- C) refraction of light
4.) When the objects is placed at 2F. the image fromed by a convex lens will be at-
c) Between F and 2F
d) Between F and optical centre
Ans-c) between F and 2F
Answer the following questions.
1.) What do you understand by refraction?
Ans- when light passes from one optical medium to another it bends at the line of contact of the two medium such bending of light rays is called refraction of light.
Refraction is seen in light. For refraction of light medium is necessary.
2.) When the light ray enters water medium through glass medium ,where will it defect- towards normal or away from the normal?
Ans- when the light ray enters water medium through glass medium it will defect towards normal
3.) What do you understand by refractive index of a medium?
Ans-refractive index is the refraction by any medium is measured by its deviation in terms of refractive index. Refractive index is the unit to express the optical density of a medium. When refractive indices is more than 1, then the light ray is moving from rarer medium to a denser medium. It shifts towards the normal ,When the refractive index is less than 1 then the light is moving from denser to rarer medium and it deviates away from normal . all this happed in case of refractive index of medium.
4.) What is long sightedness? How can it be rectified ? explain with diagram
Ans- Long sightedness is the type of eye defect in which the focal length of the eye increases due to this the image of the nearly objects us formed beyond the retina this is known as long sightedness. This defect can be rectified by using an eye glasses with convex lens. The lens turn the rays in such a way that the rays focus properly on the retina.