Question

Three point charges $q_1=1$ NC, $q_2=-3$ nC and $q_3=+5$ nC are located at x = 2 cm, x = 4cm and x = 0 respectively. Then,

• A. The x-component of the force on $q_3$ is $-28\mu N$
• B. The x-component of the force on $q_3$ is $+56\mu N$
• C. The y-component of the force on $q_3$ is zero
• D. The y-component of the force on $q_3$ is nonzero

Answer 1

Answer: (A), (C)

The correct options are
A The x-component of the force on $q_3$ is $-28\mu N$
C The y-component of the force on $q_3$ is zero


$F_{3x}=F_{13}-F_{23}$
$=\frac{1}{4\pi {ϵ}_0}[\frac{1\times {10}^{-9}\times 5\times {10}^{-9}}{(0.02{)}^2}-\frac{3\times {10}^{-9}\times 5\times {10}^{-9}}{(0.04{)}^2}]$
$=28\mu N$
$F_{3y}=0$