Focal length of convex lens is 100 cm and focal length of concave lens is 8 cm. Find the magnification of the given combination of lens if object is placed at point O.

Question

Focal length of convex lens is 100 cm and focal length of concave lens is 8 cm. Find the magnification of the given combination of lens if object is placed at point O. (A) 1.02 (B) 0.04 (C) 2.01 (D) 0.08

Tardigrade Admin · Accepted Answer

For first lens m1=(v/u)=(f/u+f)=(100/-50+100)=2 Image distance v = 2u = 2 Ã (-50) = -100 cm For second lens Now u = - 190 cm, f = - 8 cm, m2 = ? m2=(v/u)=(f/u+f)=(-8/-190-8)=0.04 Net magnification = m1 m2 = 0.08

Q. Focal length of convex lens is $100 c m$ and focal length of concave lens is $8 c m$ . Find the magnification of the given combination of lens if object is placed at point $O$ .

1.02

0.04

2.01

0.08

For first lens
$m_{1} = \frac{v}{u} = \frac{f}{u + f} = \frac{100}{- 50 + 100} = 2$
Image distance v = 2u = 2 × (-50) = -100 cm
For second lens
Now u = - 190 cm, f = - 8 cm, m₂ = ?
$m_{2} = \frac{v}{u} = \frac{f}{u + f} = \frac{- 8}{- 190 - 8} = 0.04$
Net magnification = m₁ m₂ = 0.08

Q. Focal length of convex lens is 100cm and focal length of concave lens is 8cm. Find the magnification of the given combination of lens if object is placed at point O.