Question

An object is placed at a distance of 20cm from a convex lens of focal length 30cm.find the distance of the image from the lens.​

Answer 1

Answer:

using lens formula:

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

v=image distance from lens

u=object distance from lens

f=focal length of lens

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

$\frac{1}{v} = \frac{1}{30} + \frac{1}{20}$

$\frac{1}{v} = \frac{2 + 3}{60}$

$\frac{1}{v} = \frac{5}{60}$

$\frac{1}{v} = \frac{1}{12}$

inverting this,we get:

v=12m.

This is the distance of the image from the lens.

hope it helps...

plzzz mark brainliest....

Answer 2

✸Question ✸

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▪ An object is placed at a distance of 20cm from a convex lens of focal length 30cm.find the distance of the image from the lens?

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✰Answer ✰

Given :-

➤ Object Distance (u) = -20 cm

➤Focal length (f) = +30 cm.

To find :-

➤ Image Distance??

★Solution ★

➠ By using lens formula

$\frac{1}{v} - \frac{1}{u} = \frac{1}{f} \\ \\ \frac{1}{v} - \frac{1}{ (- 20)} = \frac{1}{30} \\ \\ \frac{1}{v} = \frac{1}{20} - \frac{1}{30} \\ \\ \frac{1}{v} = \frac{30 - 20}{600} \\ \\ \frac{1}{v} = \frac{10}{600} \\ \\ v = \frac{600}{10} \\ v = + 60 \: cm$

Hence ,image distance is 60 CMO.

✰Magnification ✰

$m = \frac{v}{u} \\ \\ m = \frac{60}{ - 30} \\ \\ m = - 2$

Hence magnification is -2 cm

✰Nature of Image ✰

➠Image formed is Real ,Inverted and enlarged