CBSE Class 10 Physics Refraction of Light Worksheet Set 02

Question. You are given three media A, B and C of refractive index 1.33, 1.65 and 1.46. The medium in which the light will travel fastest is
(a) A
(b) B
(c) C
(d) equal in all three media

Answer : B

Question. A 10 mm long awl pin is placed vertically in front of a concave mirror. A 5 mm long image of the awl pin is formed at 30 cm in front of the mirror. The focal length of this mirror is
(a) -30 cm
(b) -20 cm
(c) -40cm
(d) -60 cm

Answer : B

Question. 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 the size of the object?
(a) 15 cm in front of the mirror
(b) 30 cm in front of the mirror
(c) between 15 cm and and 30 cm in front of the mirror
(d) more than 30 cm in front of the mirror

Answer : B

Question. Under which of the following conditions a concave mirror can form an image real and larger than the actual object?
(a) When the object is kept at a distance equal to its radius of curvature
(b) When object is kept at a distance less than its focal length
(c) When object is placed between the focus and centre of curvature
(d) When object is kept at a distance greater than its radius of curvature

Answer : C

Question. A mirror and a lens each have focal length of -15 cm. The mirror and the 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, but the lens is concave

Answer : A

Question. The path of a ray of light coming from air passing through a rectangular glass slab traced by four students are shown as A, B, C and D in figure. Which one of them is correct? 
(a) A
(b) B
(c) C
(d) D

Answer : B

Question. The refractive index of transparent medium is greater than one because
(a) Speed of light in vacuum < speed of light in tansparent medium (b) Speed of light in vacuum > speed of light in tansparent medium
(c) Speed flight in vacuum = speed of light in tansparent medium
(d) Frequency of light wave changes when it moves from rarer to denser medium

Answer : B

Question. An object at a distance of 30 cm from a
concave mirror gets its image at the same point. The focal length of the mirror is
(a) – 30 cm
(b) 30 cm
(c) – 15 cm
(d) +15 cm

Answer : C

Question. Beams of light are incident through the holes A and B and emerge out of box 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) A convex lens .
(c) A concave lens
(d) A prism

Answer : A

Question. The refractive index of water is 1.33. The speed of light in water will be
(a) 1.33 × 108 m/s
(b) 3 × 108 m/s
(c) 2.26 × 108 m/s
(d) 2.66 × 108 m/s

Answer : C

Question. Image formed by reflection from a plane mirror is
(a) real and inverted
(b) virtual and erect
(c) real and erect
(d) virtual and inverted

Answer : B

Question. Magnification produced by a rear view mirror fitted in vehicles
(a) is less than one
(b) is more than one
(c) is equal to one
(d) can be more than or less than one depending upon the position of the object in front of it.

Answer : A

Question. The velocity of light is maximum in a medium of
(a) glass
(b) water
(c) vacuum
(d) diamond

Answer : C

Question. A child is standing in front of a magic mirror. She finds the image of her head bigger, the middle portion of her body of the same size and that of the legs smaller. The following is the order of combinations for the magic mirror from the top.
(a) Plane, convex and concave
(b) Convex, concave and plane
(c) Concave, plane and convex
(d) Convex, plane and concave

Answer : C

Question. Which of the following can make a parallel beam of light when light from a point source is incident on it?
(a) Concave mirror as well as convex lens
(b) Convex mirror as well as concave lens
(c) Two plane mirrors placed at 90° to each other
(d) Concave mirror as well as concave lens

Answer : A

Question. Large number of thin stripes of black paint are made on the surface of a convex lens of focal length 20 cm to catch the image of a white horse. The image will be
(a) a zebra of black stripes
(b) a horse of black stripes
(c) a horse of less brightness
(d) a zebra of less brightness

Answer : C

Question. Which of the following statements is/are true? 
(a) A convex lens has 4 dioptre power having a focal length 0.25 m
(b) A convex lens has -4 dioptre power having a focal length 0.25 m
(c) A concave lens has 4 dioptre power having a focal length 0.25 m
(d) A concave lens has – 4 dioptre having a focal 0.25 m

Answer : A

Question. The image formed by a convex lens can be
(a) virtual and magnified
(b) virtual and diminished
(c) virtual and of same size
(d) virtual image is not formed

Answer : A

Question. The nature of image formed by a convex mirror when the object distance from the mirror is less than the distance between pole and focal point (F) of the mirror would be
(a) real, inverted and diminished in size
(b) real, inverted and enlarged in size
(c) virtual, upright and diminished in size
(d) virtual, upright and enlarged in size

Answer : C

Question. Focal length of a concave mirror is
(a) negative
(b) positive
(c) depends on the position of object
(d) depends on the position of image

Answer : A

Question. The image formed by concave mirror is real, inverted and of the same size as that of the object. The position of object should be
(a) at the focus
(b) at the centre of curvature
(c) between focus and centre of curvature
(d) beyond centre of curvature

Answer : C

Question. In torches, search lights and headlights of vehicles the bulb is placed
(a) between the pole and the focus of the reflector
(b) very near to the focus of the reflector
(c) between the focus and centre of curvature of the reflector
(d) at the centre of curvature of the reflector

Answer : B

Question. Which mirroji can produce a virtual, erect and magnified ifhage of an object?
(a) Concave mirror
(b) Convex mirror
(c) Plane mirror
(d) Both concave and convex mirrors

Answer : A

Question. If a man’s face is 25 cm in front of concave shaving mirror producing erect image 1.5 times the size of face, focal length of the mirror would be
(a) 75 cm
(b) 25 cm
(c) 15 cm
(d) 60 cm

Answer : A

Question. A point object is placed at a distance of 20 cm from a convex mirror of focal length 20 cm. The image will form at:
(a) at infinity
(b) at focus
(c) at the pole
(d) behind the mirror

Answer : D

(a) Both the Assertion and the Reason are correct and the Reason is the correct explanation of the Assertion.
(b) The Assertion and the Reason are correct but the Reason is not the correct explanation of the Assertion.
(c) Assertion is true but the Reason is false.
(d) The statement of the Assertion is false but the Reason is true.

Question. Assertion: Cannot see the distant object clearly.
Reason: The far point of an eye suffering j, from myopia is less than infinity.

Answer : B

Question. Assertion: Pupil is black in colour.
Reason: Pupil is black in colour as no light is reflected in it.

Answer : A

Question. Assertion: The rainbow is a man made spectrum of sunlight in the sky.
Reason: The rainbow is formed in the sky when the sun is shining and it is raining at the same time.

Answer : A

Question. Assertion: Incident light is reflected in only one direction from a smooth surface.
Reason: Since the angle of incidence and the angle of reflection are same, a beam of parallel rays of light falling on a smooth surface is reflected as a beam of parallel light rays in one direction only.

Answer : A

Question. Assertion: The word AMBULANCE on the hospital vans is written in the form of its mirror as
Reason: The image formed in a plane mirror is same size of the oblect.

Answer : B

Fill in the Blanks :

Question. The focal length of a concave lens is considered to be ____________ .
Answer: negative

Question. Power of’ a lens is the ………. of its focal length.
Answer: reciprocal

Question. The refractive index of a transparent medium is the ratio of the speed of light in ____________ to that in the ____________ .
Answer: vacuum, medium

Question. If the magnification has a minus sign, then the image is ____________ and ____________ .
Answer: real, inverted

Question. The focal length of a lens is the distance between ____________ and ____________ of the lens.
Answer: optical centre, principal focus

Question. A ………. lens will always give a virtual, erect and diminished image, irrespective of the position of the object.
Answer: concave

Question. In order to calculate the power of a lens, we need its focal length in ____________ .
Answer: metres

Important Questions for NCERT Class 10 Science Light Reflection and Refraction