Question

an object of height 40 cm is placed at a distance of 30 cm from the optical centre of convex lens of focal length 20cm draw a ray diagram to find the position and size of the image formed mark optical centre and principal focus on the diagram also find the approximate ratio of size of the image to the size of the object ​

Answer 1

Explanation:

ho -40

u -30

focal length +20 CM

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

we know f and u value,change formula

1/v=1/u+1/f

1/v=1/30+1/20

1/v=2x1+3x1/60

1/v=5/60

v=12

magnification=hi/ho=v/u

hi=v/uxho

hi=12/-30x40

hi=-48/3

hi=-16

hence make the ray diagram all q are solved