CBSE Class 10 Physics Light Reflection and Refraction MCQs Set F

Question: A concave mirror gives an image that is virtual, erect and magnified. Where is the object placed?
a) At focus
b) Between focus and centre of curvature
c) At pole
d) Between pole and focus
Answer: d

Question: The focal length of a spherical mirror of radius of curvature 30 cm is:
a) 10 cm
b) 15 cm
c) 20 cm
d) 30 cm
Answer: b

Question: The power of a lens is +2.0 D. Its focal length should be:
a) 100 cm
b) 50 cm
c) 25 cm
d) 40 cm
Answer: b

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 the combinations for the magic mirror from top to bottom.
a) Plane, convex and concave
b) Convex, concave and plane
c) Concave, plane and convex
d) Convex, plane and concave
Answer: c

Question: In order to obtain a magnification of –0.6 with a concave mirror, the object must be placed:
a) At the focus
b) Between pole and focus
c) Between focus and centre of curvature
d) Beyond the centre of curvature
Answer: d

Question: Magnification produced by a convex mirror is always:
a) More than 1
b) Less than 1
c) Equal to 1
d) More or less than 1
Answer: b

Question: A student obtained a sharp inverted image of a distant tree on the screen placed behind a convex lens. He then removed the screen and tried to look through the lens in the direction of the object. He would now observe:
a) A blurred image on the wall of the laboratory
b) An erect image of the tree on the lens
c) No image as the screen has been removed
d) An inverted image of the tree at the focus of the lens
Answer: d

Question: When an object is kept at any distance in front of a concave lens, the image formed is always:
a) Virtual, erect and magnified
b) Virtual, inverted and diminished
c) Virtual, erect and diminished
d) Virtual, erect and same size as object
Answer: c

Question: The angle of refraction is greater than the angle of incidence when a ray passes from:
a) Glass to air
b) Water to glass
c) Air to glass
d) Glass to water
Answer: a

Question: Magnification produced by a plane mirror is:
a) Less than one
b) Greater than one
c) Zero
d) Equal to one
Answer: d

Question: A converging lens is used to produce an image of an object on a screen. What change is needed for the image to be formed nearer to the lens?
a) Increase the focal length of the lens
b) Insert a diverging lens between the lens and the screen
c) Increase the distance of the object from the lens
d) Move the object closer to the lens
Answer: c

Question: Rays from the Sun converge at a point 15 cm in front of a concave mirror. Where should an object be placed so that the 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 30 cm in front of the mirror
d) More than 30 cm in front of the mirror
Answer: b

Question: Which of the following can form a virtual image which is always smaller than the object?
a) A plane mirror
b) A convex lens
c) A concave lens
d) A concave mirror
Answer: c

Question: A ray of light travelling in air goes into water. The angle of refraction will be:
a) 90°
b) Smaller than the angle of incidence
c) Equal to the angle of incidence
d) Greater than the angle of incidence
Answer: b

Question: The image formed by a concave mirror is real, inverted and same size as the object when the object is placed:
a) At F
b) At infinity
c) At C
d) Beyond C
Answer: c

Question: The laws of reflection hold true for:
a) Plane mirrors only
b) Concave mirrors only
c) Convex mirrors only
d) All reflecting surfaces
Answer: d

Question: A ray of light passes from glass into air. The angle of refraction will be:
a) Equal to the angle of incidence
b) Greater than the angle of incidence
c) Smaller than the angle of incidence
d) 45°
Answer: b

Question: The focal length of a lens having power –0.25 D is:
a) –4 cm
b) –400 mm
c) –4 m
d) –40 m
Answer: c

Question: While determining the focal length of a concave mirror, you try to focus the image of a distant object formed by the mirror on the screen. The image formed on the screen, as compared to the object, should be:
a) Erect and highly diminished
b) Inverted and enlarged
c) Erect and enlarged
d) Inverted and highly diminished
Answer: d

Question: In order to obtain a real image twice the size of the object with a convex lens of focal length 15 cm, the object distance should be:
a) More than 5 cm but less than 10 cm
b) More than 10 cm but less than 15 cm
c) More than 15 cm but less than 30 cm
d) More than 30 cm but less than 60 cm
Answer: c

Question: Linear magnification produced by a concave mirror may be:
a) Less than 1 or equal to 1
b) More than 1 or equal to 1
c) Less than 1, more than 1 or equal to 1
d) Less than 1 or more than 1
Answer: b 

Question: A student carries out the experiment of tracing the path of a ray of light through a rectangular glass slab for two different values of angle of incidence ∠i = 30° and ∠i = 45°. In the two cases the student is likely to observe the set of values of angle of refraction and angle of emergence as:
a) ∠r = 30°, ∠e = 20° and ∠r = 45°, ∠e = 28°
b) ∠r = 30°, ∠e = 30° and ∠r = 45°, ∠e = 45°
c) ∠r = 20°, ∠e = 30° and ∠r = 28°, ∠e = 45°
d) ∠r = 20°, ∠e = 20° and ∠r = 28°, ∠e = 28°
Answer: c

Question: A student determines the focal length of a device ‘X’ by focusing the image of a distant object on a screen placed 20 cm from the device on the same side as the object. The device ‘X’ is
a) Concave lens of focal length 10 cm
b) Convex lens of focal length 20 cm
c) Concave mirror of focal length 10 cm
d) Concave mirror of focal length 20 cm
Answer: d

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: A small bulb is placed at the focal point of a converging lens. When the bulb is switched on, the lens produces:
a) A convergent beam of light
b) A divergent beam of light
c) A parallel beam of light
d) A patch of coloured light
Answer: c

Question: To determine the approximate focal length of the given convex lens by focussing a distant object (say, a sign board), you try to focus the image of the object on a screen. The image you obtain on the screen is always:
a) Erect and laterally inverted
b) Erect and diminished
c) Inverted and diminished
d) Virtual, inverted and diminished
Answer: c

Question: A teacher sets up the stand carrying a convex lens of focal length 15 cm at 42.7 cm mark on the optical bench. He asks four students A, B, C and D to suggest the position of screen on the optical bench so that a distinct image of a distant tree is obtained almost immediately on it. The positions suggested by the students were as:
a) 12.7 cm
b) 29.7 cm
c) 57.7 cm
d) 72.2 cm
Answer: a

Question: A student has focused on the screen a distant building using a convex lens. If he has selected a blue coloured building as object, select from the following options the one which gives the correct characteristics of the image formed on the screen.
a) Virtual, erect, diminished and green shade
b) Real, inverted, diminished and in violet shade
c) Real, inverted, diminished and in blue shade
d) Virtual, inverted, diminished and in blue shade
Answer: c

Question: A student determines the focal length of a device by focusing the image of the sun on a screen placed 20 cm from the device on the same side as the sun. The correct statement about the device is:
a) Convex mirror of focal length 12 cm
b) Convex lens of focal length 24 cm
c) Concave mirror of focal length 24 cm
d) Convex lens of focal length 12 cm
Answer: c

Question: Three students A, B and C focused a distant building on a screen with the help of a concave mirror. To determine focal length of the concave mirror they measured the distances as given below:
Student A: from mirror to the screen
Student B: from building to the screen
Student C: from building to the mirror
Who measured the focal length correctly?
a) Only A
b) Only B
c) A and B
d) B and C
Answer: a

Question: In order to determine the focal length of a concave mirror by obtaining the image of a distant object on screen, the position of the screen should be:
a) Parallel to the plane of concave mirror
b) Perpendicular to the plane of concave mirror
c) Inclined at an angle 60° to the plane of mirror
d) In any direction with respect to the plane of concave mirror
Answer: a

Question: Where should an object be placed in front of the concave mirror so as to obtain its virtual, erect and magnified image ?
Answer: between pole and focus

Question: For which positions of the object does a concave mirror produce an inverted, magnified and real image ?
Answer: between focus and centre of curvature

Fill in the following blanks with suitable words :

Question: Parallel rays of light are reflected by a concave mirror to a point called the ………… principal
Answer: focus

Question: The focal length of a concave mirror is the distance from the ……….to the mirror.
Answer: principal focus

Question If the magnification has a plus sign, then image is……………and………….
Answer: virtual ; erect

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

Question A concave mirror………….rays of light whereas a convex mirror……….rays of light.
Answer: converges ; diverges

Question: When light is reflected, the angles of incidence and reflection are………. .
Answer: equal

Question: For a convex mirror, parallel rays of light appear to diverge from a point called the………. principal focus
Name the spherical mirror which has :
a) virtual principal focus.
b) real principal focus.
Answer: a) Convex mirror b) Concave mirror

Question: Out of convex mirror and concave mirror, whose focus is situated behind the mirror ?
Answer: convex mirror

Question: Find the focal length of a concave mirror whose radius of curvature is 32 cm.
Answer: 16 cm