Two positive point charges are arranged as shown below on a y-axis. The charges
ID: 2239086 • Letter: T
Question
Two positive point charges are arranged as shown below on a y-axis. The charges and there locations are are: q1 = +11.6 nC at (0, 6.50) mm and q2 = +5.9 nC at the origin. http://www.webassign.net/userimages/ChargesOnY.jpg?db=v4net&id=128674
a. What is the x-coordinate of the point where a third charge (q3=96.9nC) could be placed so that the net electric force onq3is 0?
mm
b. How would you describe the y-coordinate of this point (where the net electric force onq3is zero) (try to answer this before doing any calculations)?
Explanation / Answer
a) The electric feild produced by the two charges must be zero on that point on x axis
k q1/(x^2+ 6.5^2) + k q2/x^2 =0
since both q1 and q2 are positive there is no such ppoint possible on x axis.
b) logically the point will be between 0 and 3.25.sinceboth the charges are positive the third charge shouls lie between the two. it should be far from the higher charge and closer to the smaller one.
c) k q1/(6.5-y)^2 - k q2/y^2 =0
y= 2.7 mm
d) it wuld be same regardless of q3 value. once the feild is zero whatever charge may be kept on the point but it wont experience any force.