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QNEET-2018-Ph-880: NEET 2018 Physics - Class 12 NEET-2018-Ph-880 Solution: An object is placed at a distance of 40 cm from a concave…
An object is placed at a distance of 40 cm from a concave mirror of focal length 15 cm. If the object is displaced through a distance of 20 cm towards the mirror the displacement of the image will be 30 cm away from the mirror 36 cm away from the mirror 30 cm towards the mirror 36 cm towards the mirror
Multiple Choice Options
- A 30 cm away from the mirror
- B 36 cm away from the mirror
- C 30 cm towards the mirror
- D 36 cm towards the mirror
Step-by-Step Verified Solution
Using mirror formula,
1 f = 1 v 1 + 1 u 1
1 _ 15 = 1 v 1 _ 1 40
_ v 1 = �24 cm
When object is displaced by 20 cm towards
mirror.
Here u 2
= �20
So, 1 f = 1 v 2 + 1 u 2
1 _ 15 = 1 v 2 _ 1 20
_ v 2 = -60 cm
So, the image will be shift away from mirror by
(60 � 24) cm = 36 cm.