two point charges 1 0 micro C and -0 25 micro coloumb are placed in air at a distance 0 - Physics - Electric Charges And Fields

Question

two point charges 1 0 micro C and -0 25 micro coloumb are placed in
air at a distance 0 40m from each other find out at wich point on
the line joining the two charges should a third charge be placed so
that no force acts upon it?

Vara · Accepted Answer

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Let third Q be placed at a point P from charge q1 (- 0 25 micro
coulomb)

Condition for equilibrium, that is, no force acts upon
third charge:

Attraction force between q1 and Q = Repulsion force between q2 and
Q

Magnitude of charge, q1=0
25 μCMagnitude of charge, q2=1 μCHence, from Coulombs law,kq1Qx2=kq2Qd+x2d+xx2=q2q1d+xx=q2q11+dx=q2q1dx=q2q1-1x=dq2q1-1  =0
410 25-1 =0 41 =0
4 m (from charge of -0
25 micro coulomb)

two point charges 1.0 micro C and -0.25 micro coloumb are placed in air at a distance 0.40m from each other.find out at wich point on the line joining the two charges should a third charge be placed so that no force acts upon it?