A convex lens of power +2.5 D is in contact with a concave lens of focal length 25 cm. The power of combination is

Question

A convex lens of power +2.5 D is in contact with a concave lens of focal length 25 cm. The power of combination is (A) -1.5 D (B) 0 D (C) +1.5 D (D) +6.5 D

Tardigrade Admin · Accepted Answer

Power of concave lens =-(1/0.25)=-4 D Adding combination =-4 D +2.5 D =-1.5 D

Q. A convex lens of power $+ 2.5 D$ is in contact with a concave lens of focal length $25 c m$ . The power of combination is

-1.5 D

0 D

+1.5 D

+6.5 D

Power of concave lens $= - \frac{1}{0.25} = - 4 D$
Adding combination $= - 4 D + 2.5 D = - 1.5 D$

Q. A convex lens of power +2.5D is in contact with a concave lens of focal length 25cm. The power of combination is

-1.5 D

0 D

+1.5 D

+6.5 D

Power of concave lens =−0.251​=−4D Adding combination =−4D+2.5D=−1.5D

Q. A convex lens of power $+ 2.5 D$ is in contact with a concave lens of focal length $25 c m$ . The power of combination is

Power of concave lens $= - \frac{1}{0.25} = - 4 D$
Adding combination $= - 4 D + 2.5 D = - 1.5 D$