Question

Three lenses in contact have a combined focal length of 12 cm. When the third lens is removed, the combined
focal length is
60
7
cm. The third lens is
(1) A converging lens of focal length 30 cm
(2) A converging lens of focal length 60 cm
(3) A diverging lens of focal length 30 cm
(4) A diverging lens of focal length 60 cm
​

Answer 1

Answer:

(3) A diverging lens of focal length 30 cm