Ask Questions, Get Answers

Want to ask us a question? Click here
Browse Questions
0 votes

A convex lens of focal length 40 cm is kept in contact with a concave lens of focal length 25 cm. What is power of this combined lens system.

$(a)\;+6.50\;D \\ (b)\;-6.50\;D \\ (c)\;+1.5\;D \\ (d)\;-1.5 \;D $

Can you answer this question?

1 Answer

0 votes
$P_1 =\large\frac{1}{f_1 \;in\; meter}$
$\qquad= \large\frac{100}{40}$$=2.5 D$
$P_2 =\large\frac{-100}{25}$$=-4D$
$\quad = P_1+P_2=-1.5 D$
Hence d is the correct answer.
answered Jan 17, 2014 by meena.p

Related questions

Ask Question
student study plans
JEE MAIN, CBSE, AIPMT Mobile and Tablet App
The ultimate mobile app to help you crack your examinations
Get the Android App