Question

an object is placed along the principal axis of a thin converging lens that has a focal length of 14 cm. if the distance from the object to the lens is 21 cm, what is the distance from the image to the lens

Answer 1

42 cm

Step-by-step explanation:

For a converging lens, the focal length is positive:

f = +14 cm

In this problem, the distance of the object from the lens is 21 cm:

p = +21 cm

The distance of the image from the lens can be found by using the lens equation:

`(1)/(f)=(1)/(p)+(1)/(q)`

where q is the image distance. Solving the formula for q and substituting the numbers, we find

`(1)/(q)=(1)/(f)-(1)/(p)=(1)/(14 cm)-(1)/(21 cm)=(1)/(42 cm)\\q= 42 cm`