Two lenses of power 3D and -ID are kept in contact. What is the focal length and nature of the combined lens?
A. 50 cm, convex
B. 200 cm, convex
C. 50 cm, concave
D. 200 cm, concave
Answer:A
Two lenses of power 3D and -ID are kept in contact. What is the focal length and nature of the combined lens?
A. 50 cm, convex B. 200 cm, convex C. 50 cm, concave D. 200 cm, concave