Question

An object placed 98 cm in front of a converging lens forms an image 8 cm behind the lens. What is the focal length of the lens?

Answer 1

7.4 cm

Explanation:

Given:

Object distance (o) = 98 cm

Image distance (i) = 8 cm

We can determine the focal length using the following formula:

`\begin{gathered} (1)/(f)=(1)/(o)+(1)/(i) \\ \\ \text{ We replacing:} \\ \\ (1)/(f)=(1)/(98)+(1)/(8) \\ \\ (1)/(f)=(98+8)/(98\cdot8) \\ \\ f=(98\cdot8)/(98+8)=(784)/(106) \\ \\ f=7.396\cong7.4\text{ cm} \end{gathered}`

The focal length of the lens is 7.4 cm