Question:

Three charge q, Q and 4q are placed in a straight line of length l at points distant 0, $\frac{1}{2}$ and l respectively from one end. In order to make the net froce on q zero, the charge Q must be equal to

Updated On: Jul 7, 2022
  • - q
  • -2q
  • $\frac{-q}{2}$
  • q
Hide Solution
collegedunia
Verified By Collegedunia

The Correct Option is A

Solution and Explanation

$\left(F_{net }\right)_{q} = 0 $ $\Rightarrow k \frac{Qq}{\left(\frac{\ell}{2}\right)^{2}} + k \frac{4q^{2}}{\ell^{2}} = 0$ $k = \frac{1}{4\pi\varepsilon_{0}}$ $ \Rightarrow 4Qq + 4q^{2} = 0$ $ \Rightarrow Q = - q $
Was this answer helpful?
0
0

Top Questions on Electric Field

View More Questions

Notes on Electric Field

Concepts Used:

Electric Field

Electric Field is the electric force experienced by a unit charge. 

The electric force is calculated using the coulomb's law, whose formula is:

\(F=k\dfrac{|q_{1}q_{2}|}{r^{2}}\)

While substituting q2 as 1, electric field becomes:

 \(E=k\dfrac{|q_{1}|}{r^{2}}\)

SI unit of Electric Field is V/m (Volt per meter).