Q. 384.3( 4 Votes )
Three identical c
Answer :
Given:
Value of three identical charges: q = 1.0× 10–8 C
Side of the equilateral triangle: l = 20cm = 0.2m
From the diagram,
A,B and C are the three vertices having equal charge q.
EA,EB and Ec are the electric fields at the center of the triangle due to charges A,B and C respectively.
h is the height of the equilateral triangle
and r is the distance from the center of the triangle to it’s all three vertices.
Formula used:
Formula for potential at a point is:![]()
Where k is a constant and k=
=9× 109 Nm2C-2 .q is the point charge and r is the distance between the centre of the triangle and the vertex.
Since charges are equal at A,B and C:
The Field from B and C are resolved into horizontal and vertical components as seen from the figure.
Here θ is 30° as every angle of an equilateral triangle is 60o .
The horizontal components balance each other.
Therefore net electric field ,
Enet = EA -(EB sinθ+ECsinθ)
∴Enet= E-(Esinθ+Esinθ)
∴Enet = E(1-sin(30)-sin(30) )
∴Enet =E(1-0.5-0.5)
∴Enet =0
Thus, the electric field at the center of the given equilateral triangle is zero.
Now, using Pythagoras theorem to find value of h,![]()
![]()
We know that, in an equilateral triangle
Thus we get,![]()
![]()
Since Electric field is same for all three points: VA=VB=VC
The potential at the center is :![]()
![]()
![]()
![]()
Hence , potential at the centre of the triangle is 2341 V and Electric field at the center is zero.
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