If u is the object distance and v the image distance, which of the following expressions gives the linear magnification produced by a convex lens of focal length f?
- A.u/f – f
- B.u/v + f
- C.v/f + 1
- D.v/f – 1
Correct Answer: Option D
Explanation
Magnification, M = v/u = v (1/u)
And for the Lens formula 1/u + 1/v = 1/f
=> 1/u = 1/f – 1/v
∴M = V(1/u)
= V(1/f – 1/v) = v/f – v/v = v/f – 1
∴M = v/f – 1