– Two thin converging lenses of focal lengths 15 cm and 20 cm are co-axially 10 cm apart. Calculate the equivalent focal length.
A. 12 cm
B. 16 cm
C. 20 cm
D. 35 cm
Answer:A
– Two thin converging lenses of focal lengths 15 cm and 20 cm are co-axially 10 cm apart. Calculate the equivalent focal length.
A. 12 cm B. 16 cm C. 20 cm D. 35 cm