Question

A 2.5 cm tall object is placed
perpendicular to the principal axis
a convex lens of focal length 15 cm.
The distance of the object from the
lens is 30 cm. Find the Nature,
Position and Size of the image.​

Answer 1

Step-by-step explanation:

The size of the image is 10 cm and the image is real and inverted.

Explanation:

Given that,

Height of object h = 5 cm

Focal length f = 20 cm

The distance of the object u = -30 cm

Using lens's formula

\dfrac{1}{f}=\dfrac{1}{v}-\dfrac{1}{u}

f

1

=

v

1

−

u

1

\dfrac{1}{20}=\dfrac{1}{v}-\dfrac{1}{-30}

20

1

=

v

1

−

−30

1

\dfrac{1}{v}=\dfrac{1}{60}

v

1

=

60

1

v = 60v=60

The image is formed at 60 cm on the other side from the lens.

The magnification is

m = \dfrac{v}{u}m=

u

v

m = \dfrac{60}{-30}m=

−30

60

m = -2m=−2

The image is real, inverted .

Size of the image,

m = \dfrac{h'}{h}m=

h

h

′

-2 = \dfrac{h'}{5}−2=

5

h

′

h' = -10 cmh

′

=−10cm