If the power of a lens is -2D, what is its focal length?(a) +50 cm (b) -100 cm< (c) -50 cm (d) +100 cm

(c) -50 cm   


Explanation  

Given,
Power of lens = P = $-2D$. 
As, power is in negative sign $(-)$, it means it is a diverging lens or concave lens.

We know that, 
$Power=\frac{1}{focal\ length\ (in\ meters)}$
Putting the given value in the formula we get-
$-2=\frac{1}{f}$
$f=\frac{1}{-2}$
$f=0.5m$
$f=50cm$
Hence, the focal length of the combination will be $50cm$.

Tutorialspoint
Tutorialspoint

Simply Easy Learning

Updated on: 10-Oct-2022

1K+ Views

Kickstart Your Career

Get certified by completing the course

Get Started
Advertisements