Question

If lens I has a focal length of + 15 cm and lens II has a focal length of + 30 cm. Which lens has more power?

• A. lens I
• B. lens II
• C. power of lens is independent of focal length
• D. none of these

Answer 1

The correct option is A

lens I

($P_{{lens}_{|}}$) = $\frac{1}{15}$ = 0.06 D

($P_{{lens}_{||}}$) = $\frac{1}{30}$ = 0.033 D

${\left(Power\right)}_{{lens}_{|}}$ > ${\left(Power\right)}_{{lens}_{||}}$