Question

An object is placed at a distance 20 cm a convex lens of focal length 10 cm . find the image distance and nature of the image. ​

Answer 1

Answer:

Image distance = 6.67 cm

Explanation:

u= -20cm. f= 10cm

1 = 1 - 1

10 v. 20

Upon solving, v=20/3 cm or 6.67 cm

The image is virtual and erect.

Answer 2

GIVEN :

object distance (u)= - 20 cm

(object distance is always negative)

focal length (f) = 10 cm

(focal length of convex lens is positive)

SOLUTION :

(1) 1/f = 1/v - 1/u

1/10= 1/v + 1/20

1/v = 1/10-1/20

1/v = 20-10/200

1/v = 10/200

v = 20 cm

the image is formed of the opposite side of the lens

(2)

m= v/u = 20/-20 = -1

the image is inverted

the image has same size as that of the object