Question

Your camera determines the focal distance required for your picture to be in focus using the lens equation, 1/F - 1/S = 1/D, where the focal distance to the object from the lens (D) is related to the focal length (F) and the distance from the lens to the film (S). If an object is placed 8 cm from a lens with a focal length of 4 cm, how far from the lens is the image (film) formed?

a) 2 cm
b) 4 cm
c) 8 cm
d) 12 cm

Answer 1

The image (film) is formed 8 cm from the lens.

Step-by-step explanation:

The lens equation, 1/F - 1/S = 1/D, relates the focal length (F), the distance from the lens to the object (D), and the distance from the lens to the film (S). In this question, the object is placed 8 cm from a lens with a focal length of 4 cm. To find the distance from the lens to the film (image), we can substitute the given values into the lens equation.

1/F - 1/S = 1/D

1/4 - 1/S = 1/8

Solving for S, we find that the distance from the lens to the image (film) is 8 cm.