Question

1- Find electric field intensity due to dipole of dipole moment 4.4x10^-19C-m at a point 30nm away along bisector axis?

2- A point charge of 1x 10^-6C is at centre of Gaussian surface with cubical shape 1m on edge. Find flux through surface? 

3- Consider a point charge 2C, what is the radius of equipotential surface having potential 20V? 

Answer 1

Answer

1-electric field due to dipole is

$E=\frac{kp}{r^3}$

= $\frac{9\times10^9\times4.4\times10^{-19}}{27\times 10^{-24} }$

$=1.46\times10^{14}V/m$

2-flux through all surface

$\phi=\frac{q}{\epsilon_0}=\frac{10^{-6}}{8.85\times{10^{-12}}}=11.30\times{10^{4}}$V-m

3-radius of equipotential surface is given by

$r=\frac{kq}{V}=\frac{9\times10^9\times2}{20}=9\times10^8m$