A converging lens of focal length 5.0cm is placed in contact with a diverging lens of focal length 10.0cm. Find the combined focal length of the system.

A converging lens of focal length 5.0cm is placed in contact with a di

1.	A converging lens of focal length 5.0cm is placed in contact with a diverging lens of focal length 10.0cm. Find the combined focal length of the system.
Answer» SOLUTION :Here `f_1=+5.0cm and f_2=-10.0cm` THEREFORE, the combined FOCAL length F is GIVEN by `1/F=1/f_1+1/f_2=1/5.0-1/10.0=+ 1/10.0` `therefore F=+10.0cm` i.e, the combination behaves as a converging lens of focal length 10.0cm