A convex lens of power + 6D is placed in contact with a concave lens of power - 4 D. What is the nature and focal length of the combination-
1
Concave, 25 cm
2
Convex, 50 cm
3
Concave, 20 cm
4
Convex, 100 cm
A convex lens of power + 6D is placed in contact with a concave lens of power - 4 D. What is the nature and focal length of the combination-