Question

two point charges +40 micro coulombs each are placed 20 cm apart
a)what is the electric field at the midpoint of dipole
b)what is the force acting on a charge 10^-5C if it is placed at the midpoint​

Answer 1

Given:

Two point charges each measuring + 40 micro C are placed 20cm apart.

To find:

• Electrostatic field at the midpoint
• Force acting on a 10^(-5) C if it's placed at the midpoint.

Calculation:

1st part:

At the midpoint both the charges shall exert equal and opposite electrostatic field intensity as a result of which then it field intensity at that position will be zero.

$E_{net} = \dfrac{k \times (40 \times {10}^{ - 6} )}{ {(0.1)}^{2} } -\dfrac{k \times (40 \times {10}^{ - 6} )}{ {(0.1)}^{2} }$

$= > \: E_{net} = 0$

Hence net Electrostatic Field Intensity at the midpoint will be zero.

2nd part:

Force experienced by any charge can be calculated from the product of of magnitude of charge and the electrostatic field intensity at any point on the field.

$\therefore \: force = \: E_{net} \times q$

$= > \: force = \: E_{net} \times {10}^{ - 5}$

$= > \: force = \: 0 \times {10}^{ - 5}$

$= > \: force = \: 0 \: newton$

So , net force experienced by the charge will be zero at that point.