# Class 10 Light Reflection and Refraction Important Questions

Light Reflection and Refraction Important Questions

1. What is the focal length of a plane mirror ?
2. Draw a ray diagram to show refraction of a light ray in a glass slab.
3. A converging lens has a focal length of 15 cm. An object is placed 60 cm from the lens . Find the position, nature & size of the image.
4. Refractive index of diamond with respect to glass is 1.6 and absolute refractive index of glass is 1.5. Find the absolute refractive index of diamond.
5. It is desired to obtain an erect image of an object using a concave mirror of focal length 20 cm.
1. What should be the range of distance of object from the mirror.
2. Will the image be bigger or smaller than object ?
3. Draw a ray diagram to show the image formation in this case.
6. One half of a convex lens of focal length 20 cm is covered with a black paper.
1. Will the lens produce a complete image of the object ?
2. Show the formation of image of an object placed at 2F1 of such covered lens with the help of a ray diagram.
3. What will be the intensity of the image formed by half covered lens as compared to non-covered lens.
7. If the angle of incidence of a ray of light falling on glass surface is 60o and the angle of refraction is 30o. What is the refractive index of glass ?
8. Rays from sun converge at a point 15 cm in front of a concave mirror. Where should an object be placed so that size of its image is equal to size of object.
9. Size of image of an object by a mirror having a focal length of 20 cm is observed to be reduced to 1/3rd of its size. At what distance the object has been placed from the mirror? What is the nature of image and the mirror?
10. A 10 mm long awl pin is placed vertically in front of a concave mirror. A 5 mm image of awl pin is formed at 30 cm in front of the mirror. What is the focal length of this mirror?
11. If a child crawls towards a plane mirror at a rate of 0.20 m/s, then at what speed will the child and her image come nearby to each other?
12. A ray of light is propagating from medium A to B. If the refractive index of medium B with respect to A is 1.5, what will be the refractive index of medium A with respect to B?
13. State snell’s law with the help of suitable ray diagram.
14. Which mirror is used for rear view in vehicles and why? 