Question

a needle 10 cm high is placed at 40 cm from a convex lens of focal length 15 cm. Find position, nature and size of image. Also draw ray diagram.

Answer 1

Answer:

Given that

u= -10 cm

f= 15 cm

Find out

We need to find v

Formula

We know the formula

1/f = 1/v + 1/u

Therefore, 1/v= 1/f – 1/u

Substituting the known values in the above equation we get,

1/v= 1/15 + 1/10

1/v = (2+3)/30 (lcm)

Hencev=5/30 = 6 cm

v= 6cm

Nature of the image: The image is formed behind the mirror and it is virtual and erect.