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?

Question

3878 views around the world

You can reuse this answer
Creative Commons License

Answer 1 · 2018-03-13T16:27:27

#1.5cm#

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#