Question

an object 5 cm in length is held 25cm away from a convex lens of focal and 10 cm. draw the ray diagram and find the position size and the nature of the image formed.

Answer 1

According to the Question

h = 5 cm

u = - 25 cm

f = + 10 cm

v = ?

Nature = ?

Object is placed at 25 cm and focal length 10 cm then object is placed beyond the convex lens

Using lens Formula

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

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

$\bf\huge\frac{1}{v} = \frac{1}{10} - \frac{1}{25}$

$\bf\huge\frac{1}{v} = \frac{3}{50}$

$\bf\huge v = \frac{50}{3}$

= v ⇒ 16.67 cm

Magnification = $\bf\huge\frac{h1}{h} = \frac{v}{u}$

$\bf\hugeh1 = h\times \frac{v}{u}$

$\bf\huge = 5\times \frac{16.67}{-25}$

= -3.33 cm

Image = Real , Inverted

Formed at the distance of 16.67 other side of lens

Answer 2

H=5

U=-25

F=10

By lens formula

1/f=1/v-1/u