A system consists of two charges 4 μ C and -3 μ C with no external field placed at (-5 cm, 0, 0) and (5 cm, 0, 0) respectively. The amount of work required to separate the two charges infinitely away from each other is

Question

A system consists of two charges 4 μ C and -3 μ C with no external field placed at (-5 cm, 0, 0) and (5 cm, 0, 0) respectively. The amount of work required to separate the two charges infinitely away from each other is (A) -1.1 J (B) 2J (C) 2.5 J (D) 3 J

Tardigrade Admin · Accepted Answer

Here, q1=4 μ C, q2=-3 μ C, r=10 cm=0.1 m Electrostatic potential energy, U=(1/4πε0) (q1q2/r)=9×109×(4×10-6×(-3)×10-6/0.1) =-1.1 J

Q. A system consists of two charges $4 μ C$ and $- 3 μ C$ with no external field placed at $(- 5 c m, 0, 0)$ and $(5 c m, 0, 0)$ respectively. The amount of work required to separate the two charges infinitely away from each other is

$- 1.1 J$

$2 J$

$2.5 J$

$3 J$

Here, $q_{1} = 4 μ C, q_{2} = - 3 μ C, r = 10 c m = 0.1 m$
Electrostatic potential energy,
$U = \frac{1}{4 π ε _{0}} \frac{q _{1} q _{2}}{r} = 9 \times 1 0^{9} \times \frac{4 \times 1 0 ^{- 6} \times ( - 3 ) \times 1 0 ^{- 6}}{0.1}$
$= - 1.1 J$

Q. A system consists of two charges 4μC and −3μC with no external field placed at (−5cm,0,0) and (5cm,0,0) respectively. The amount of work required to separate the two charges infinitely away from each other is

−1.1J

2J

2.5J

3J