Question

Which of the following is the lens formula?

• A. $\frac{1}{f}=\frac{1}{v}-\frac{1}{u}$
• B. $\frac{1}{f}=\frac{1}{v}+\frac{1}{u}$
• C. $\frac{1}{v}=f-\frac{1}{u}$
• D. $\frac{1}{f}=v+\frac{1}{u}$

Answer 1

The correct option is A

$\frac{1}{f}=\frac{1}{v}-\frac{1}{u}$

The lens formula is given as $\frac{1}{f}=\frac{1}{v}-\frac{1}{u}$, where f- focal length, u- object distance from the lens and v- image distance from the lens. The lens formula is implemented with proper sign convention using cartesian method.