Question

Q1.an object is placed at a distance of 30 cm from a convex lens of focal length 20 cm . find the position of image​.

Answer 1

Explanation:

Given :

Object is placed at a distance of 30 cm from a convex lens.

Focal length of the lens is 20 cm .

To Find :

Position of Image .

Solution :

$\longmapsto\tt{Object\:Distance\:(u)=-30\:cm}$

⟼ObjectDistance(u)=−30cm

$\longmapsto\tt{Focal\:Length\:(f)=20\:cm}$

Using Formula :

$\longmapsto\tt\boxed{Mirror\:Formula=\dfrac{1}{f}=\dfrac{1}{v}-\dfrac{1}{u}}$

Putting Values :

$\longmapsto\tt{\dfrac{1}{f}+\dfrac{1}{u}=\dfrac{1}{v}}$

$\longmapsto\tt{\dfrac{1}{20}+\dfrac{1}{(-30)}=\dfrac{1}{v}}$

$\longmapsto\tt{\dfrac{1}{20}-\dfrac{1}{30}=\dfrac{1}{v}} \\ </p><p> \\ \longmapsto\tt{\dfrac{3-2}{60}=\dfrac{1}{v}}</p><p> </p><p> \\ </p><p></p><p> </p><p></p><p> \\ \longmapsto\tt{\dfrac{1}{60}=\dfrac{1}{v}}</p><p> </p><p> </p><p> </p><p> \\ \\ </p><p></p><p>\longmapsto\tt\bf{60\:cm=v}</p><p>$

So , The Position of the image is 60 cm and the image formed is real and inverted .