Question

An electric dipole consists of two charges + 10 UC and -10 UC separated by a distance of 5 mm. Calculate the electric field at a point on the axial line due to the dipole at a distance of 10 cm from the centre of the dipole?

Answer 1

Answer:

Electric field at that point = 9×10⁵ N / C

Explanation:

Given that,

Charge of the dipole = q = 10μC = 10×10⁻⁶ = 10⁻⁵ C

Dipole length = 2a = 5mm = 5×10⁻³ m = 0.005 m

Distance of point from centre = r = 10cm = 0.1 m

Since r >>> 2a ,

Electric field due to dipole at axial line = k × 2p/r³

We know that,

p = 2a × q

p = 0.005 × 10⁻⁵

p = 5×10⁻⁸

k = 1 / 4πε₀ = 9×10⁹

r = 0.1m

Putting these values in we get,

E at axial point = 9×10⁹×2×5×10⁻⁸ / (0.1)³

                         = 9×10⁹×10×10⁻⁸ / (10⁻³)

                         = 9×10⁹⁻⁸⁺¹⁺³

                         = 9×10⁵ N / C