Search any question & find its solution
Question:
Answered & Verified by Expert
An optician prescribes a corrective lens of power $+2 \mathrm{D}$, then the focal length of the required convex lens is
Options:
Solution:
1553 Upvotes
Verified Answer
The correct answer is:
$50 \mathrm{~cm}$
Power of a lens in diopters, $P=\frac{100}{f}$ $f=$ Focal length of lens in $\mathrm{cm}$. here,
$$
P=+20 \mathrm{D}
$$
so,
$$
2=\frac{100}{f(\mathrm{~cm})} \Rightarrow f(\mathrm{~cm})=\frac{100}{2}=50
$$
$\therefore$ Focal length of lens $=50 \mathrm{~cm}$.
$$
P=+20 \mathrm{D}
$$
so,
$$
2=\frac{100}{f(\mathrm{~cm})} \Rightarrow f(\mathrm{~cm})=\frac{100}{2}=50
$$
$\therefore$ Focal length of lens $=50 \mathrm{~cm}$.
Looking for more such questions to practice?
Download the MARKS App - The ultimate prep app for IIT JEE & NEET with chapter-wise PYQs, revision notes, formula sheets, custom tests & much more.