Question

An object is placed at a distance of 10cm from a lens of power 4D.find the position and nature of the image formed

Answer 1

Heya Frnd ...........☺

$P = \frac{100}{f} cm$

=> f = 100 / P

=>✴ f = 100/4 = 25 cm✴

Now,

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

$= > \: \frac{1}{v} = \: \frac{1}{f} + \frac{1}{u}$

$= > \: \frac{1}{v} = \: \frac{1}{25} + \: \frac{1}{ - 10}$

$= > \: \frac{1}{v} = \: \frac{2 - 5}{50}$

$= > \: v \: = \: \frac{ - 50}{3}$

$= > \: v \: = \: - 16.66 \: cm$

. . . . . . . . . . . . . . . . . . . ☺ ANS ☺

Answer 2

Hey friend !!

Here is your answer.

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Given,

Power = 4 D

u = - 10cm

f = ?

v = ?

As we know , P = 100 / f

==> f = 100 / 4

==> f = 25

Now ,

==> 1 / f = 1 / v - 1 / u

==> 1 / v = 1 / f + 1 / u

==> 1 / v = 1 / 25 + 1 / (-10)

==> 1 / v = (2 - 5) / 50

==> v = (- 50) / 3

==> v = - 16.66 cm

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Hope it helps.

#pragya_singh