Question

In an optics experiment, with the position of the object fixed, a student varies the position of a convex lens and for each position, the screen is adjusted to get a clear image of the object. A graph between the object distance u and the image distance n, from the lens, is plotted using the same scale for the two axes. A straight line passing through the origin and making an angle of 45° with the x-axis meets the experimental curve at P. The coordinates of P will be :

• A. (2f, 2f)
• B. $\left( \frac { f } { 2 } , \frac { f } { 2 } \right)$
• C. (f, f )
• D. ( 4f, 4f )

Answer 1

Answer: (A)

(2f, 2f)

Answer 2

For concave lens

Straight line which is passing through origin cut at points

(– 2f, 2f) but magnitude (+2f, +2f).