Question

a convex lens of focal length 10cm and a concave lens of focal length 15cm are placed in contact. find power of combination and focal length?

class 10, chapter light​

Answer 1

Answer:

3.3D

Explanation:

the net power when we keep 2 lens in contact is the summ of their individual powers

power of the convex lens =1/10cm=100/10D=10D as the length is in cm(note that the focal length is positive for convex lens)

power of the concave lens =1/15cm=100/15D= -6.6D(note that for concave lens the focal length is negative)

Net power =P1+P2=10D-6.6D=3.3D

Hope it helps have a great day ahead