Que-2: If in the question (1) given above the object is placed symmetrically between the mirrors, then the number of images formed will be :

(a) n
(b) n + 1
(c) n – 1
(d) 0

Ans: (c) n – 1
Hint-  Same as Que-1

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Que-3: Two plane mirrors are placed making an ange 60° in between them. For an object placed in between the mirrors, the number of images formed will be .

(a) 3
(b) 6
(c) 5
(d) infinite.

Ans: (c) 5
Hint-
n = 360°/θ°
= 360°/60° = 6 
If n=360°/θ° is even, the number of images is always n – 1 for all positions of object in between the mirrors.
Hence, number of images formed
= n – 1
= 6 – 1
= 5
Hence, the number of images formed will be 5

Que-4: In a barber’s shop, two plane mirrors are placed:

(a) perpendicular to each other
(b) parallel to each other
(c) at an angle of 60° between them
(d) at an angle of 45° between them.

Ans: (b) parallel to each other
Hint- In a barber’s shop, in order to see the hairs at the back of the head two plane mirrors are placed parallel to each other at the front and at the back of the viewer.

Que-5: For two mirrors kept parallel to each other, the number of images formed is :

(a) 5
(b) 7
(c) 0
(d) infinity

Ans: (d) infinity
Hint-  When two mirrors are kept parallel to each other, i.e., θ = 0 then n = 360°00360°​ = infinite. Hence, we get infinite number of images.

Que-6: The number of images formed for two mirrors kept perpendicular to each other is :

(a) 1
(b) 2
(c) 3
(d) 5

Ans: (c) 3
Hint-  When two mirrors are kept perpendicular to each other i.e., θ = 90°,
then n = 360°/90°​ = 4,
n = 4, is even so number of images is n – 1
Therefore,
n – 1
= 4 – 1
= 3
Hence, for two mirrors kept perpendicular to each other, three images are formed for an object kept in between them.

Que-7: A thick plane mirror, silvered at its back, forms multiple number of images. Out of these, the brightest image is :

(a) first image
(b) second image
(c) third image
(d) All are of equal brightness

Ans: (b) second image
Hint- A thick plane mirror forms a number of images due to multiple reflections within the glass from front surface and back reflecting surface. Out of these, the second image formed due to reflection from the back reflecting surface is the brightest.

Que-8: How many plane mirrors are used in a periscope and kaleidoscope ?

(a) 2 and 3 respectively
(b) 3 each
(c) 3 and 2 respectively
(d) 2 and 4 respectively

Ans: (a) 2 and 3 respectively
Hint-  In a periscope two parallel plane mirrors each inclined at 45° with the vertical walls are placed facing each other. In a kaleidoscope three plane mirrors inclined with each other at 60° are used.

Que-9: In a kaleidoscope, three plane mirrors are inclined with each other at an angle of :

(a) 0°
(b) 30°
(c) 60°
(d) 90°

Ans: (c) 60°
Hint-  In a kaleidoscope three plane mirrors inclined with each other at 60° are used.

Que-10: In a periscope, two plane mirrors are inclined at an angle of …………… with the vertical walls.

(a) 0°
(b) 30°
(c) 45°
(d) 60°

Ans: (c) 45°
Hint- In a periscope two parallel plane mirrors each inclined at 45° with the vertical walls are placed facing each other.