Question

A 4cm tall object is placed perpendicular to the principal axis on a convex lens to focal length 12cm . the distance to a object from the lens is 18cm.find the nature, position and size of the image also find the magnification​

Answer 1

Given that, a 4 cm tall object is placed perpendicular to the principal axis on a convex lens to focal length 12 cm. The object distance from the lens is 18 cm.

We have to find the nature, position, size of the image and magnification.

From above data we have; h is 4 cm, f is 12 cm and u is -18 cm.

Using the Lens formula:

1/f = 1/v - 1/u

Substitute the known values,

→ 1/12 = 1/v - 1/(-18)

→ 1/12 - 1/18 = 1/v

→ (3 - 2)/36 = 1/v

→ 1/36 = 1/v

→ 36 = v

Therefore, the image distance from the lens is 36 cm.

Using Magnification formula:

m = v/u

Substitute the values,

→ m = 36/(-18)

→ m = -2

Also, m = h'/h

→ -2 = h'/4

→ -8 = h'

Image formed is real, inverted and larger than the object.

Answer 2

Given:

A 4cm tall object is placed perpendicular to the principal axis on a convex lens to focal length 12cm . the distance to a object from the lens is 18cm

To find:

the nature, position and size of the image also find the magnification

STEP BY STEP EXPLANATION:

Lens formula : 1/f = 1/v - 1/u

the values,

1/12 1/v 1/(-18)

1/12 - 1/18 = 1/v

(3 - 2)/36 = 1/v

1/36 = 1/v

36 = v

So the image distance from then lens is 36 cm

Magnification formula: m = v/u

the values,

m = 36/(-18)

m = -2

Also, m h'/h

2 = h'/4

8 = h'

Image formed will be real, inverted and large from the object.$.$