Question

29. Find the focal length (f) of a magnifying glass ifyou can see a diamond clearly when your eye is10 cm away from the glass, and the glass is 3 cmaway from the diamond.

Answer 1

We have the following:

`(1)/(f)=(1)/(d)+(1)/(d_0)`

replacing:

`\begin{gathered} (1)/(f)=(1)/(10)+(1)/(3) \\ (1)/(f)=0.1+0.33 \\ (1)/(f)=0.43 \\ (1)/(0.43)=f \\ f=(1)/(0.43)=2.31 \end{gathered}`

the local length is 2.31 cm