CBSE Class 10 Science Chapter-10 Light Reflection and Refraction – Free PDF Download
Free PDF download of Important Questions with Answers for CBSE Class 10 Science Chapter 10 – Light Reflection and Refraction prepared by expert Science teachers from latest edition of CBSE(NCERT) books only by CoolGyan to score more marks in CBSE board examination.
CBSE Class 10 Science Chapter-10 Light Reflection and Refraction Important Questions
CBSE Class 10 science Important Questions Chapter 10 – Light Reflection and Refraction
1 Mark Questions
1. An object is kept at a distance more than twice the focal length (F) from a concave mirror. The distance the image formed will be
(a) less then F
(b) equal to F
(c) between F and 2 F
(d) More than 2 F
Ans. (c) between F and 2 F
2. The speed of light, in a given medium is 
of its speed in vacuum. The absolute refractive index of the medium equals to
(a) 
(b) 
(c) 
(d) 
Ans. (c) between F and 2 F
3. A ray passing through the centre of curvature of a concave mirror is inclined at an angle 
to its principal axis. The angle of reflection for this ray equals
(a) 
(b) 
(c) 
(d) 90
Ans. (a)
4. Beams of light are incident through the holes C and D respectively as shown in the figure. Which of the following could be inside the box?
(a) A rectangular glass slab
(b) Convex lens
(c) Concave lens
(d) Prism
Ans. (a) A rectangular glass slab
5. What are the values of (i) Angle of incidence and (ii) Angle of reflection for normal incidence on a plane surface?
Ans. 
6. The power of a lens is -4.0 D. what is the nature of the lens?
(a) Plane
(b) Concave
(c) Convex
(d) Plano convex
Ans. (b) Concave
7. Where should an object be placed in front of a convex lens to get real image of the size of the object?
(a) At focus
(b) At 2F
(c) At Infinity
(d) Between optical centre and focus.
Ans. (b) At 2F
8.In torches, search lights and head lights of vehicles the bulb is placed
(a) Between pole and focus
(b) Very near to the focus
(c) Between focus and centre of curvature
(d) At centre of curvature
Ans. (b) Very near to the focus
9. Figure shows a ray of light as it travels from medium A to B. Refractive index of medium B with respect to A is
(a) 
(b) 
(c) 
(d) 
Ans. (a)
10. When a ray of light goes from one medium to another, there is
(a) Always a change in its speed as well as direction
(b) No change in speed and direction
(c) A change in speed but no change in direction
(d) A change in direction but constant speed.
Ans. (a) Always a change in its speed as well as direction
11. Name the mirror that can give an erect and enlarged image of an object?
Ans. Concave mirror
12. The rays, parallel to the principal axis, of a spherical mirror, actually meet at a point 20 cm distant from its pole. Identify the mirror and give its focal length.
Ans. Concave mirror and f= 20 cm
13.Name the kind of surfaces that
(i) Reflect
(ii) Refract most of the light falling on them.
Ans. (i) Concave mirror
(ii) Convex lens
14. Which type of mirror is usually used as a rear-view mirror in motor cars?
Ans. Convex mirror
15. Define one dioptre of power of a lens?
Ans. Power of a lens is one dioptre if focal length of a lens is 1 m
16. Define 1 dioptre of power of lens.
Ans. One dioptre of is defined as the power of lens having a focal length of 1 m.
17. Find the power of a concave lens of focal length 2 m.
Ans. Focal length of concave lens = – 2 m.
P = 1/f = 1/ (-2 m)
= -0.5 D
18. Which one of the following materials cannot be used to make a lens?
(a) Water
(b) Glass
(c) Plastic
(d) Clay
Ans. (d) Clay
19. The image formed by a concave mirror is observed to be virtual, erect and larger than the object. Where should be the position of the object?
(a) Between the principal focus and the centre of curvature.
(b) At the centre of curvature
(c) Beyond the centre of curvature
(d) Between the pole of the mirror and its principal focus.
Ans. (d) Between the pole of the mirror and its principal focus.
20. Where should an object be placed in front of convex lens to get a real image of the size of the object?
(a) At the principal focus of the lens.
(b) At twice the focal length
(c) At infinity
(d) Between the optical centre of the lens and its principal focus.
Ans. (b) At twice the focal length
21. A spherical mirror and thin spherical lens have each of focal length of -15 cm. the mirror and lens are likely to be
(a) Both concave
(b) Both convex
(c) The mirror is concave and the lens is convex
(d) The mirror is convex and lens is concave.
Ans. (a) Both concave
22. No matter how far you stand from a mirror, your image appears erect. The mirror is likely to be
(a) Plane
(b) Concave
(c) Convex
(d) Either concave or convex.
Ans. (d) Either concave or convex.
23. Which of the following lens would you prefer to use while reading small letters found in a dictionary?
(a) A convex lens of focal length 50 cm
(b) A concave lens of focal length 50 cm
(c) A convex lens of focal length 5 cm
(d) A concave lens of focal length 5 cm
Ans. (c) A convex lens of focal length 5 cm
24. A ray AFB is incident on a spherical mirror whose centre of curvature is 2 F. In which direction will it reflect?
Ans. It will reflect towards the object side parallel to principal axis.
25. A ray of light is incident at angle of 35° to a plane surface. What will the angle of reflection?
Ans. 550
26. How does image changes when the face is slowly moved away from inner face of a shining spoon?
Ans. As the face is moved away than after a particular time image becomes inverted.
27. Due to which property of light, sharp shadow of an object is obtained?
Ans. straight line property of the light.
28. Where is the image formed in a convex mirror, when the object is anywhere in front of it?
Ans. Between pole and focus, behind the convex mirror.
29. A person uses concave minor for shaving, where should he position his face in front of it?
Ans. Between pole and principal focus.
30. A ray of light is incident on a concave mirror along its principal axis. What will be the angle of reflection?
Ans. Angle of reflection = 0
31. What will happen to ray of light when it travels from rarer medium to a denser medium?
Ans. Bends towards the normal.
32. What does negative sign in the value of magnification of a mirror indicate?
Ans. Image is real.
33. Name the point inside the lens through which a ray of light goes undeviated?
Ans. Optical centre.
34. Which of the two has a great power? A lens of short focal length or a lens of large focal length?
Ans. Lens of short focal length.
35. Name the lens which always gives an erect and diminished image?
Ans. Concave lens.
36. Which mirror is used as rear view mirror in vehicles and why?
Ans. Convex mirror, wider field of view.
37. Define one dioptre?
Ans. One dioptre is the power of a lens of focal length one meter.
38. The size of an object is 2 cm. The magnification produced by a mirror is +1. What is the size of the image?
Ans. +2cm, because m=I/O , +1=I/2 =+2
39. When a ray of light passes from a denser medium to a rarer medium which angle is greater: angle of incidence or angle of refraction?
Ans.Angle of refractions.
40. An image formed in a spherical mirror has magnification -2. Is the image real or virtual?
Ans. Real
41. The power of a lens is -2D. Is the lens convex or concave?
Ans. Concave lens.
42. Focal length of a convex mirror is 10 cm. Find the radius of curvature of the mirror?
Ans. 20 cm.
