Question

1. Two charges each of 1µC but opposite in sign are 1cm apart. Calculate the electric field at a
point distant 10 cm from the midpoint on the axial line of the dipole .
2. The electric field due to a short dipole at a distance r on the axial line, from its midpoint is the
same as electric field at a distance r’ on the equatorial line from its midpoint. Determine the ratio r/r’.
3. An electric dipole consists of two charges +0.1µC and -0.1µC separated by a distance 2cm. The
dipole is placed in an external electric field of 105
N/C. What is the maximum torque exerted on the dipole by the field?
4. An electric dipole with a dipole moment 4× 10-9 Cm is aligned at 30o
with the direction of a
uniform electric field of magnitude 5×104 N/C. Calculate the magnitude of the torque acting on the dipole?

Answer 1

Answer:

1)-

p=q(2l)

=10^-6(1/100)

=10^-8

Eaxi=9(10^9)2(10^-8)/(1/10)^3

=180000

3)-

let +q=0.1(10^-6)

-q=-0.1(10^-6)

r=1/50m

then p=0.1(10^-6)(1/50)

p=0.2(10^-8)

E=105

torue =0.2(10^-8)(105)sin90°

=21(10^-8) ans.