Two charges 9e and 3e are placed at a separation of r. The distance of...
Let electric field at a point x from the charge 9e, is zero.
It can be written as,
1/4πε0 x 9e/x^2 = 1/4πε0 x 3e /(r−x)^2
3(r - x)^2 = x^2
√3(r − x)^2 = x^2
x = V3/(V3 + 1)r
The distance of the point from 9e charge where the electric field intensity will be zero is √3/(√3 +1)r.
This question is part of UPSC exam. View all NEET courses
Two charges 9e and 3e are placed at a separation of r. The distance of...
Problem: Two charges 9e and 3e are placed at a separation of r. The distance of point where the electric field intensity will be zero, is??
Solution:
To find the point where electric field intensity is zero, we need to consider the concept of electric field due to two point charges.
Electric Field Due to Two Point Charges:
When two point charges are separated by a distance r, the electric field at a point P, located at a distance x from the line joining the two charges, is given by:
E = (k*q1*x)/((r/2-x)^2) + (k*q2*(r-x))/((r/2+x)^2)
where k is Coulomb's constant, q1 and q2 are the charges and r is the separation between them.
At the point where the electric field is zero, the net electric field due to the two charges is zero.
So, we have:
(k*q1*x)/((r/2-x)^2) + (k*q2*(r-x))/((r/2+x)^2) = 0
Solving this equation, we get:
x = (q2*r)/(q1+q2)
Substituting the given values, we get:
x = (3er)/(9e+3e) = r/4
Hence, the distance of point where electric field intensity is zero is r/4.
Therefore, the correct option is (E) √3r/4.
Note: The HTML tags were not used as the response was within the word limit.
To make sure you are not studying endlessly, EduRev has designed NEET study material, with Structured Courses, Videos, & Test Series. Plus get personalized analysis, doubt solving and improvement plans to achieve a great score in NEET.