Download LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034

LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034
B.Sc. DEGREE EXAMINATION – PHYSICS
SUPPLEMENTARY EXAMINATION – JUNE 2009
PH 5505 - ELECTRICITY & MAGNETISM
Date & Time: 25/06/2009 / 10.00 – 1.00
Dept. No.
Max. : 100 Marks
Part-A
Answer ALL questions:
10 x 2 = 20 marks
1. Define the electric potential at a point, which is at a distance ‘r’ from the point charge ‘q’.
2. State Gauss’s law.
3. State Kirchoff’s law for electric currents in a circuit.
4. Define Thomson coefficient for a metal.
5. Give the expression for force on a current element ‘dI’ in a magnetic field ‘B’
6. State Biot-Savart’s law.
7. State two properties of a diamagnetic material.
8. What is meant by retentivity and coercivity of a magnetic material?
9. Define the resonant frequency of a LC circuit.
10. Define the ‘peak’ and ‘rms’ value of alternating current.
Part-B
Answer any FOUR questions:
4 x 7.5 = 30 marks
11. Calculate the electric potential at any point due to a charge configuration of +q and –q
separated by a distance ‘2d’.
12. Explain the determination of the conductivity of the given electrolyte using Kohlraush
bridge
13. Derive the expression for the magnetic induction at any point on the axis of a solenoid.
14. Describe a method to determine the value of a high resistance, using a B. G.
15. a). Explain ferromagnetism on the basis of domain theory.
b). Define Curie temperature
Part-C
Answer any FOUR questions:
.
4 x 12.5 = 50 marks
16. a). Obtain the expression for energy stored in a capacitor of capacitance ‘C’ with charge
‘q’ at a potential ‘V’.
b). Find out the change in energy of a parallel plate capacitor due to the introduction of
a dielectric slab of thickness ‘d’ and permittivity r (Discuss both the cases of the
charge and the potential remaining constant)
17. a). Define Thermoelectric power.
b). What is a thermoelectric diagram? Discuss various uses of thermoelectric diagrams.
18. With a neat sketch explain the principle and working of a moving coil ballistic
galvanometer, Discuss also the damping correction.
19. Discuss the growth and decay of currents in a ‘LCR’ circuit, Obtain the condition for
oscillations.
20. a).Starting from Maxwell’s equations in free space arrive at the wave equation for the
electro magnetic field.
b). Establish that these waves are transverse in nature. Calculate the velocity of these
waves in free space.