An object 5.0 cm high is placed 2.0 cm from a converging (convex) lens which is being used as a magnifying glass. The image produced is 6.0 cm from the lens and is 15 cm high.What is the focal length of the lens?

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1 Answer
Mar 13, 2018

1.5cm

Explanation:

We don't need the height of the object or image here.

From thin lens formula :-
1/f=1/d_i+1/d_o

=>1/f=1/6+1/2

LCM of 2 and 6 = 6

=>1/f=1/6+3/6

=>1/f=(1+3)/6

=>1/f=(4)/6

=>f=6/4

Flipping both sides,
=>f=3/2

=>f=1.5cm