Question

If lens $I$ has focal length $+15cm$ and lens $II$ has focal length $+30cm$, then power.

• A. lens I has more
• B. lens II has more
• C. both have same power

Answer 1

The correct option is A lens I has more

Given,
Focal length of lens $I$ = $+15cm$
Focal length of lens $II$ = $+30cm$

Power of lens $\text{P}=\frac{1}{\text{focal length}}$

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

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

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