1.Two point charges, q =8×10-8 C and Q= -2×10-8 C are separated
by a distance of 10 cm in air. What is the net electric field at the mid- point
between the charges.
Using the formulae=F/Q
=3.6x 105
2. Two point charges 4 Q, Q are separated by 1 m in air.
At what point on the line joining the charges is the electric field intensity
zero? Q9
x=2/3 m
3 .Two point charges of 16μC
and -9μC are placed 8cm apart in air. Determine the position of the point at
which resultant electric field is zero.
4 .Eight identical point
charges of q Coulomb each are placed at corners of a cube of each side 0.1m
.Calculate electric field at the center of the cube. Calculate the field at the
center when one of the corner charges is removed.
i) zero ii) E = (1.2 x 1012)q N/C
5. What are the magnitude and
direction of electric field at the center of the square in fig if q=1.0 x 10 -8C and a = 5cm?
6. A charge of 4 x 10 -9 C is
distributed uniformly over the circumference of a conducting ring of radius
0.3m. Calculate the field intensity at a point on the axis of the ring at 0.4m
from its centre, also at the center.
At the center of ring, r = 0,
So E = 0
7. Charge q1=+6.0nC is on y
axis at y=+3 cm and charge q2 = -6nCis on y axis at y=-3cm .Calculate force on
test charge q0= 2 nC placed on x axis at x=4cm.
-51.8 j μN
8.ABC is an equilateral
triangle of each side 5 cm. two charges of ±50/3 x 10-3 μC are placed
at A and B respectively. Calculate magnitude and direction of resultant
intensity at C.
6 x 104 N/C
parallel to AB from + charge to – charge.