A converging beam of light forms a sharp image on a screen. A lens is placed 10 cm from the screen in the path of the beam. It was found that the screen has to be moved 8 cm further away to obtain the sharp image. Focal length of the lens is -
Text Solution
Verified by ExpertsThe correct answer is:
C
Since the screen has to be moved away, the lens used should be concave.
= 
– 
⇒ 
= 
f = 
= – 22.5 cm
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