Question

an object placed in front of a convex lens at a distance of 25 cm on principal axis. the focal length of the lens is 15 cm at what distance the image is fformed? find the nature and size of the image

Answer 1

Explanation:

size is found by v/u

mark it BRAINLIEST

Answer 2

ANSWER:

The convex lens produces an erect, virtual and enlarged or magnified image with the image distance of 37.5 cm and magnified 1.5 times of original image size.

EXPLANATION:

The lens formula is  

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

Here u is the "object distance", v is the "image distance" and f  is the "focal length" of the lens.

The object distance is the distance of separation of the object from the lens and the image distance is the distance of separation of the image formed from the lens. As the object will be placed behind the lens so the object distance will have a negative sign. So the object distance u=-25 cm, focal length f = 15 cm.

Thus

$\frac{1}{v}-\left(\frac{1}{-25}\right)=\frac{1}{15}$

$\frac{1}{v}=\frac{1}{15}-\frac{1}{25}=\frac{25-15}{375}$

$v=\frac{375}{10}=37.5 \mathrm{cm}$

Magnification of the image is  

$\text { Magnification of image }=\frac{v}{u}=\frac{37.5}{25}=1.5$

The convex lens produces an erect, virtual and enlarged or magnified image with the image distance of 37.5 cm and magnified 1.5 times of original image size.