Chapter 1
What is the mathematical representation of Coulomb's law?
F∝ (q1×q2)/r2
What is the line integral of electric field along any closed path?
zero
What are the two kinds of dielectrics?
Polar and Non-polar
r-3
What is electrostatic shielding? How can it be achieved?
Phenomenon of making a region free of any electric field is called electrostatic shielding
Inside a conductor, field is zero. A region can be shielded by surroounding it with a conducting sheet.
What is the flux through a uniformly charged thin infinite plane sheet?
E.2A
Electric field on axial line of an electric dipole is X. Electric field on equatorial line of an electric dipole is Y.
X : Y =
-2:1
a. Expression of capacity of parallel plate capacitor in vacuum.
b. Expression of capacity of parallel plate capacitor in medium of dielectric constant k
a. C = Aε0/d
b. C' = Aε0k/d = Ck
What is the relation between electric susceptibility, Z and dielectric constant, K?
K = 1 + Z
List four characteristics of electric field lines.
1. no closed loops
2. no overlap
3. does not exist inside a conductor
4. start at positive and end at negative at right angles
5. relative closeness gives strength
6. tangent at any point gives direction
List four characteristics of equipotential surfaces.
1. no work required to move charge over the surface
2. electroc field lines are perpendicular
3. relative closeness indicates strength of field
4. no intersection
What is the time taken by an electron to cover a distance x in an electric field E?
t = (2xm/eE)1/2
a. What is the torque acting on a dipole (in vector form)?
b. What is the work done in rotating a dipole from angle θ1 to θ2 in an electric field E?
a. p x E
b. -pE(cos θ2 - cos θ1)
Two capacitors of capacitances C1 and C2 having charges q1 and q2 are connected to each other. After sharing charges,
a. What will be the common potential?
b. What will be the loss of energy as heat?
a. V = (q1 + q2)/(C1 + C2)
= (C1V1 + C2V2)/(C1 + C2)
b. Uloss = 0.5(C1C2/C1 + C2)(V1 - V2)2
What is the SI units of the following:
a. Capacitance
b. Potential gradient
c. KE of an electron
d. Electric charge
e. Dipole moment
a. Farad
b. Volt /meter
c. Joule
d. Coulomb
e. Coulomb - meter