JEE MAIN - Physics (2021 - 31st August Morning Shift - No. 4)
An object is placed at the focus of concave lens having focal length f. What is the magnification and distance of the image from the optical centre of the lens?
1, $$\infty$$
Very high, $$\infty$$
$${1 \over 2}$$, $${f \over 2}$$
$${1 \over 4}$$, $${f \over 4}$$
Explanation
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U = $$-$$f
$${1 \over V} - {1 \over U} = {1 \over { - f}} \Rightarrow {1 \over V} = - {2 \over f}$$
$$V = {{ - f} \over 2}$$
$$m = {V \over U} = {1 \over 2}$$
distance = $${f \over 2}$$
Option (c)
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