In: Physics
A charge of -4 µ C is located at (x, y) = (0, 0) and a second charge of 2 µ C is located at x = 1. (a) Find a general expression for the electric field. (b) At what point, if any, will the electric field vanish?
Charge 
 is at 
 and charge 
 is located at 
, That is the two charges lie on X-axis.
a)
Electric field vector at location 
  due to a point charge 
 located at 
 is 
Magnitude of electric field at distance 
 from a charge 
 is
b)
is left side and 
 is right side.
Distance between the two charges is 
The two charges are opposite in sign, so electric field cannot
be zero between them. Charge  
 has smaller magnitude
, so electric field will be zero at a point to the right side of
charge 
 .
Electric field due to the two charges vanishes at a distance
 to the
right of charge 
. That is at a
distance 
to the
right side of charge 
At this distance magnitude of electric fields due to the two charges must be equal ,





That is from charge 
 electric field is
zero at a distance 
 that is at 
------------------