Class 10 for MCQ Science Chapter 10 Light- Reflection and Refraction
Question 31:
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
Answer: (a) is less than one
Question 32:
On heating a liquid the refractive index
generally:
(a) Increases
(b) Decreases
(c) Does not change
(d) Increases
or decreases depending upon rate of heating
Answer
Answer: (b) Decreases
Question 33:
A lens of focal length 12 cm forms an erect image,
three times the size of the object. The distance between the object and image
is:
(a) 8 cm
(b) 16 cm
(c) 24 cm
(d) 36 cm
Answer
Answer: (b) 16 cm
Question 34:
The unit of power of lens
is
(a)
Meter
(b)
Centimeter
(c)
Diopter
(d) M-1
Answer
Answer: (c) Diopter
Question 35:
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
Answer: (b) 30 cm in front of the mirror
Question 36:
A lens has a power of +0.5D. It is:
(a) A concave
lens of local length 5 m
(b) A convex lens of focal length 2 m
(c) A convex
lens of focal length 5 m
(d) A concave lens of focal length 2 m
Answer
Answer: (b) A convex lens of focal length 2 m
Question 37:
If an object is placed 21 cm from a converging lens,
the image formed is slightly smaller than the object. If the object is placed at a
distance of 19 cm from the lens, the image formed is slightly larger than the
object. The approximate focal length of the lens is:
(a) 20 cm
(b) 18
cm
(c) 10 cm
(d) 5 cm
Answer
Answer: (c) 10 cm
Question 38:
The radius of curvature of a mirror is 20cm the
focal length is
(a)
20cm
(b)
10cm
(c)
40cm
(d) 5cm
Answer
Answer: (b) 10cm
Question 39:
A full length image of a distant tall building can
definitely be seen by using
(a) a concave mirror
(b) a convex mirror
(c) a
plane mirror
(d) both concave as well as plane mirror
Answer
Answer: (b) a convex mirror
Question 40:
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
Answer: (b) very near to the focus of the reflector