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If a charge q is placed at the centre of...

If a charge q is placed at the centre of the line joining two equal charges Q such that the system is in equilibrium then the value of q is

A

`Q//2`

B

`Q//2`

C

`Q//2`

D

`Q//2`

Text Solution

Verified by Experts

The correct Answer is:
B
Let charge `q` is placed at med point of line AB as shown below,
Also `AB= x (say)`
`AC = x/2, BC = x/ 2`

For the system to be in equilubrium
`F_(Qq) + F_(QQ) = 0`
So, `1/(4 pi varepsilon_0) (Qq)/(( x //2)^2) + 1/( 4 pu varepsilon_0 ) (QQ)/x^2 =0`
`q=- Q/4` .
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