Ray Optics

JEE Main level, single correct, medium

191 of 295

Question 191 of 295

The graph shows how the magnification mm produced by a thin lens varies with image distance vv. The focal length of the lens used is

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Answer: (A) bc\dfrac{b}{c}

For a thin lens,
∣m∣=∣1−vf∣\left|m\right|=\left|1-\dfrac{v}{f}\right|
From the above equation, slope of the line is 1f\dfrac{1}{f}
cb=1f\dfrac{c}{b}=\dfrac{1}{f}
f=bcf=\dfrac{b}{c}

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