Optics 3 Question 42
42. A pin is placed in front of a convex lens of focal length and made of a material of refractive index 1.5. The convex surface of the lens farther away from the pin is silvered and has a radius of curvature of . Determine the position of the final image. Is the image real or virtual ?
(1978)
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Answer:
Correct Answer: 42. at a distance of 11 cm, virtual
Solution:
- The given system behaves like a mirror of power given by
or
As
and
Solving this equation, we get
i.e. the system behaves as a concave mirror of focal length
Using the mirror formula
i.e. virtual image will be formed at a distance of