Two thin lenses, one of focal length +60 cm and the other of focal length -20 cm are kept in contact. Their combined focal length is
Two thin lenses, one of focal length +60 cm and the other of focal length

Q. Two thin lenses, one of focal length +60 cm and the other of focal length -20 cm are kept in contact. Their combined focal length is

A.            Minus 30 cm

B.            Plus 30 cm

C.            Minus 15 cm

D.            Plus 30 cm

Answer: Minus 30 cm
Gkseries: Gkseries.com is a premier website to provide complete solution for online preparation of different competitive exams like UPSC, SBI PO, SBI clerical, PCS, IPS, IAS, IBPS PO, IBPS Clerical exam etc. & other graduate and post-graduate exams. Learn more on about us page