Question 210 of 295

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 $v$, 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 $45^{\circ}$ with the x-axis meets the experimental curve at $P$. The coordinates of $P$ will be

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

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Answer: (A) $(2 f, 2 f)$

It is possible when object kept at centre of curvature.
$$\begin{aligned} & u=v \\ & u=2 f, v=2 f . \end{aligned}$$