Optics Question 647

Question: A convex lens of power + 6D is placed in contact with a concave lens of power ? 4D. What is the nature and focal length of the combination

[AMU (Engg.) 1999]

Options:

A) Concave, 25 cm

B) Convex, 50 cm

C) Concave, 20 cm

D) Convex, 100 cm

Show Answer

Answer:

Correct Answer: B

Solution:

$ P=P _{1}+P _{2}\Rightarrow P=+6-4=+2D. $

So focal length $ f=\frac{100}{2} $ = + 50 cm; convex lens



NCERT Chapter Video Solution

Dual Pane