Question

If two convex lenses having focal length 4cm,6cm then the resultant focal length of the two lenses when they are in contact is​

Answer 1

Answer:

4+6=10 so the resultant focal length is 10 cm

Answer 2

Answer:

f=1/f1+1/f2

=1/4+1/6

=10/24

=5/12

=0.4167

Hence, the resultant focal length is 0.4167cm.