Home » Ask & Discuss » Physics. » Electricity « Back to Discussion

Electricity

Hot goIITian

Joined:	9 Mar 2010
Post:	142

17 Mar 2010 10:46:21 IST

0 People liked this

288

a certain charge is divided into Q and Q-q...what should be Q in terms of q so as to maximize repuls

None

a certain charge is divided into Q and Q-q...what should be Q in terms of q so as to maximize repulsion between two charges?????

Share this article on:

Comments (3)

Dasvidaniya

Blazing goIITian

Joined: 9 May 2009

Posts: 831

17 Mar 2010 10:57:28 IST

Like 2 people liked this

F = K Q .(Q- q) / r^2

dF/dq = K. d/dq ( Qq -q^2) =0

q =Q /2 ,

and d^2 F/ dq^2 is negative

so force will be maximum at q = Q / 2

shivanshi asthana

Hot goIITian

Joined: 9 Mar 2010

Posts: 142

17 Mar 2010 14:22:11 IST

Like 0 people liked this

thanks..

edison

Forum Expert

Joined: 19 Oct 2006

Posts: 7452

22 Jun 2011 20:17:38 IST

Like 0 people liked this

Force of repulsion between the given two charges is :

F = K Q .(Q- q) / r²

For Force 'F' to be maximum,

dF/dQ = 0

or K (Q - q) / r² + k Q / r²=0

or (Q - q) + Q = 0

or Q = q / 2

q =Q /2

Quick Reply

Reply

	Some HTML allowed.
	Keep your comments above the belt or risk having them deleted.
	Signup for a avatar to have your pictures show up by your comment
	If Members see a thread that violates the Posting Rules, bring it to the attention of the Moderator Team

Free Sign Up!

Preparing for IIT-JEE ?

Arihant Revision Package for IIT JEE - Books, Practice Tests + Rank Predictor

@ INR 1,995/-

For Quick Info

Find Posts by Topics

Physics.

Topics

9128

19728

3590

2097

7393

2756

2568

Mathematics.

Chemistry.

Biology

Institutes

Parents

Board

Fun Zone