Question

4.0 μC and –1.0 μC charges are kept fixed at A and B as shown. Find x if a charged particle at C experiences no net coulomb force.

1 cm

2 cm

3 cm

4 cm

Answer 1

Given:

4.0 μC and –1.0 μC charges are kept fixed at A and B as shown.

To find:

Value of x when charge C doesn't experience any force?

Calculation:

This question is based on NEUTRAL POINT BETWEEN UNLIKE CHARGES.

• The neutral point will be nearer to the smaller charge.

• See diagram.

• Since question digram is not provided, let's assume that distance between charge is d.

• Neutral point at N.

$\therefore \: E1 = E2$

$\implies \: \dfrac{k(4)C}{ {(d + x)}^{2} } = \dfrac{k(1)C}{ {x}^{2} }$

$\implies \: \dfrac{2}{d + x} = \dfrac{1}{ x }$

$\implies \: 2x = d + x$

$\implies \: x = d$

So, value of x is d.

• Now, you can match the options depending on the value of 'd' given in question.