The point charges -q and -9q are placed at a distance R apart. Where should a third point charge be placed so that it is in equilibrium
Answers
Answer:
Type your question...
12th
Physics
Electric Charges and Fields
Coulomb's Law and Its Applications
Two fixed point charges - ...
PHYSICS
Two fixed point charges −q and +2q and are placed at a certain distance apart. Where should a third point charge be placed so that it is in equilibrium?
December 30, 2019avatar
Aisha Chaurasiya
SHARE
VIDEO EXPLANATION
ANSWER
The force on a charge Q due to another charge q at a distance d is given by: F=
4πϵ
0
1
d
2
The force is attracting for charges of opposite signs and repelling for same sign.
Since the force is proportional to the charge of other particle, and inversely proportional to square of distance, under equilibrium,
4πϵ
0
1
d
1
2
Q(−q)
+
4πϵ
0
1
d
2
2
Q(+2q)
=0
⟹d
2
=
2
d
1
The charge Q cannot be between the charges, because otherwise both −q and +2q would exert forces in same direction.
Hence, the charge lies on line joining two charges and on left of −q because the distance of Q from −q, d
1
is lesser than that from +2q, d
2
.