Question

Focal length of a concave lens is 10cm to get an image at 6cm distance, find distance of the object. Also find magnification.​

Answer 1

Explanation:

1/f=1/v-1/u

1/u=1/v-1/f

=1/-6-(1/-10)

=1/-6+1/10

=+3-5/30

=-2/30

u=-15m

m=v/u

=-6/-15

m=0.4

Answer 2

Answer:

The correct answer of this question is $m=0.4$

Explanation:

Given - Focal length of a concave lens is 10cm to get an image at 6cm distance .

To Find - Find distance of the object and magnification.​

$\frac{1}{f} = \frac{1}{v} - \frac{1}{u}$

$\frac{1}{u} = \frac{1}{v} - \frac{1}{f}$

$=$ $\frac{1}{-6} - \frac{1}{-10}$

$= \frac{1}{-6} + \frac{1}{10}$

$= \frac{+3-5}{30}$

$= \frac{2}{30}$

$u=-15m$

$m = \frac{v}{u}$

$m = \frac{-6}{-15}$

$m=0.4$

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