Class: X Physics
Chapter: Light-Reflection and Refraction
1. What is light? What is its nature?
2. What is the speed of light in vacuum?
3. What is a mirror?
4. What is the focal length of a plane mirror?
5. Differentiate between real and virtual images.
6. What type of image is formed on a cinema screen?
7. A concave mirror is a part of a sphere of radius 40 cm. What is
the focal length of the mirror?
8. Radius of curvature of a mirror is +20 cm. What type of mirror
is it?
9. Magnification of a mirror is +2/3. What type of mirror is it?
10. Complete the following diagrams:-
C F P O F C
11. Magnification of a mirror is ‘—1’. What type of mirror is it?
What is the position of the object and image? Give the nature
of the image.
12. Name the type of mirror used:-
(i) as a reflector in search light (iii) by the dentist
(ii) as side view mirror in vehicles. (iv) as a shaving mirror
13. Wherever you may stand in front of a mirror, your image is
always erect & same sized, what type of mirror is it?
0
14. (a) A ray of light strikes the mirror at an angle of 20 . What is
the angle of reflection?
(b) Give the angle of incidence and reflection for normal
incidence.
15. A candle is kept in front of the plane mirror at a distance of 15
cm. What is the distance between candle & its image?
16. Radius of curvature of a mirror is +24cm. Name the kind of
mirror and give the characteristics of the image formed by it.
17. Define refraction.
18. State the laws of refraction.
19. How does the lateral displacement depend upon:- (a)
Thickness of the glass slab. (b)
Angle of incidence
20. What is the lateral displacement when a ray of light falls
normally on a glass slab?
21. Refractive index of water with respect to air is 1.33, what is
the refractive index of air with respect to water?
22. Under what condition, the angle of refraction will be equal to
the angle of incidence?
23. Refractive index of glass is 1.65, what is the speed of light in
glass?
24. If refractive indices of alcohol & water are 1.36 and 1.33
respectively, which of the two is optically denser?
25. A 1 cm high object is placed at a distance of 2F from a convex
lens, what is the height of the image formed?
26. Focal length of a lens is 25 cm. What is its power?
27. Where should an object be placed for using a convex lens as a
magnifying glass?
28. Power of a lens is 0.4 D. What is its focal length?
29. Why does a stick, partly immersed in water, appear to be bent?
Explain with a diagram.
30. A small electric lamp is placed at the focus of a convex lens.
What is the nature of the beam of light produced by the lens?
31. Light travels from rarer medium 1 to denser medium 2.
Angles of incidence & refraction are 450 & 300 resp.
(i) Calculate the refractive index of the second medium with
respect to the first.
(ii) Calculate the refractive index of the first medium with
respect to the second.
32. Find the position, nature and size of the image of an object 3
cm high placed at a distance of 9 cm from a concave mirror of
focal length 18 cm. (v = 18 cm, h = 6 cm)
33. An object 4 cm high is placed 40 cm in front of a concave
mirror of focal length 20 cm. Find the distance from the
mirror, at which a screen can be placed to obtain a sharp
image. (v= - 40cm)
34. A convex lens has a focal length of 30 cm. At what distance
should an object be placed from the lens so that it forms an
image at 60 cm on the other side of the lens? Find the
magnification produced by the lens. ( u = - 60cm, m = -1)
35. An arrow 2.5cm high is placed at a distance of 25 cm from a
diverging mirror of focal length 20 cm. Find the nature,
position and size of the image formed. (11.1, 1.11cm).
36. The image formed by a convex mirror of focal length 30 cm is
a quarter of the object, what is the distance of the object from
the mirror? ( -90 cm)
37. An erect image 3 times the size of the object is obtained with
a concave mirror of radius of curvature 36 cm. Calculate the
position of the object. (-12cm)
38. A concave lens has a focal length of 15 cm. at what distance
should an object be placed from the lens so that it forms an
image at 10 cm from the lens? Find the magnification of the
lens.
(-30cm, 1/3)
39. A 2 cm tall object is placed perpendicular to the principal axis
of a convex lens of focal length 10 cm. the distance of the
object from the lens is 15 cm. find the nature, position and
size of the image. (30cm, -4cm)
40. The image obtained with a convex lens is erect and its length
is 4 times the length of the object. If the focal length of the
lens is 20 cm, calculate the object and image distance.
(-15 cm, - 60cm)
41. A concave lens of focal length 25 cm and a convex lens of
focal length 20 cm are placed in contact with each other. What
is the power of this combination? What is the focal length of
the combination? (1D, 1m)
42. Find the focal length and nature of the lens which should be
placed in contact with a lens of focal length 10 cm so that the
power of the combination becomes 5 dioptre.
(-20cm, concave)
