Optics Question 640

Question: If a convex lens of focal length 80 cm and a concave lens of focal length 50 cm are combined together, what will be their resulting power

[CBSE PMT 1996; AFMC 2002]

Options:

A) + 6.5D

B) - 6.5 D

C) + 7.5 D

D) - 0.75 D

Show Answer

Answer:

Correct Answer: D

Solution:

P=1F=1f1+1f2=1(+0.8)+1(0.5)=0.75 D



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