Question

if the object is placed 30 cm away from a convex lens of focal length 15 cm. Find the distance of the
image from the lens​

Answer 1

Answer:

given,

focal length ( f) = 15cm

object distance ( u) = 30cm

image distance ( v)= ?

this is convex lens

sign convention tell us that focal length should be positive.

and object distance should be negative.

f = +15

u = -30

lens formula = 1÷v - 1÷ u= 1÷ f (1)

now putting value in equation 1

1÷v - 1÷ -30 = 1÷15

1÷v =1÷-30+1÷15

15+ (-30)÷-450

1÷v = -15÷-450 = 1÷30

v= 30 cm