Question

Read the following and answer all the questions .
________________________
An object of length 5 cm is placed at right angle to the principal axis of a mirror A and the image formed is having a length of 10cm. Without
changing the position of object, the mirror A is replaced by the mirror B having same principal axis and same pole. This results to an image of
length 2.5 cm at the same position as the earlier one. Mirror B is replaced by the plane mirror C at the same position and a virtual image is formed behind mirror at a distance of 20 cm from it. Mirror C is now replaced by
mirror A and the position of the object which is kept fixed so far, is now changed by 40cm in the direction away from the pole and, of course Keeping the object perpendicular to the principal axis. This image so
obtained has a magnification m. Replacing mirror A by
mirror B and keeping the object in its new position the image so obtained has magnification m'.
________________________
(1) Which of the following is correct ?
• mirror A is convex and B is
also convex .
• mirror A is concave and B is
also concave .
• mirror A is concave and B is
convex .
• mirror A is convex and B is
concave .

(2) The value of m'
• 4
• -4
• 1/4
• -1/4

(3) Ratio of focal length of mirror A and B is
• -2
• 1/2
• -1/2
• 1

(4) Length of mirror A and B are respectively
• - 20 cm , - 40 cm
• 10 cm , - 20 cm
• - 40 cm , 20 cm
• 60 cm , - 60 cm

(5) The value of m is
• 2
• -2
• 1/2
• -1/2​

Answer 1

Explanation:

2) The value of m'

• 4

(3) Ratio of focal length of mirror A and B is

• -2

(4) Length of mirror A and B are respectively

• - 20 cm , - 40 cm

(5) The value of m is

• 1/2

Answer 2

Answer:

1. mirror A is concave and B is convex

2. -4

3. -1/2

5. -2

Explanation:

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