Ask Questions, Get Answers

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

Two metal balls of same radii are charged to 5 and -25 units of electricity . They are brought in contact with each other and then again seperated to original distance. Ratio of magnitude of force b/w two balls after and before contact is

$(A)\;5:4\\ (B)\;4:5 \\ (C)\; 1:5 \\ (D)\;5:1 $

Can you answer this question?

1 Answer

0 votes
$F_{\large before }=\large\frac{1}{4 \pi \in _0} \frac{(5) \times (-25)}{r^2}$
Charge after $=q_1=q_2=\large\frac{5+ (-25)}{2}$
$F_{\large after }=\large\frac{1}{4 \pi \in _0} \frac{(-10) \times (-10)}{2}$
$\large\frac{|F_{\Large after}|}{|F_{\Large before}|}=\bigg| \large\frac{(-10) \times (-10)}{(5) \times (-25)}\bigg|$
$\qquad= \large\frac{4}{5}$
Hence B is the correct answer.
answered Jan 3, 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