physics pass 2th sem 2014 previous year Bsc question paper | Assam University
2014
TDC Even Semcstcr Exam
PHYSICS
(Pass)
( 2nd Semester )
Paper No. : PHSP—201
(Electricity and Magnetism)
Full Marks: 35
Pass Marks: 12
Time: 2 hours
The figures in the margin indicate full marks for the questions
Answer five questions, selecting one from each Unit
UNIT—I
1. (a) What are electric dipole and electric dipole moment? Dcrivc an cxpreion for the electric field at any point due to an electric dipole.
(b) Derive an expression for the energy stored in unit volume in presence of an electric field.
2. (a) Define electric potential. Show that the potential difference between any two points in an electric field is given by the line integral of the electric field taken over any path joining those points.
(b) Establish the relation
E=-∇V
where the symbols have their usual meanings.
UNIT—II
3. (a) Define the following :
(i) Magnetic induction
(ii) Intensity of magnetisation
(iii) Magnetic susceptibility
(iv) Magnetic permeability
(b) Establish the relation
μ=μo(1+X)
where the symbols have their usual meanings.
4. (a) What iire dia-, para— and lèrro-magnetic inutet inI? I )iscus thcir atomic origins.
(ii) What ii ii zriiigtwtlc dipolc?
UNIT—Ill
5. (a) State and explain Kirchhoff’s laws of distribution of currents in an electrical network.
(b) Deduce the condition of ‘balance of a Wheatstone bridge by using Kirchhoff’s laws.
6. (a) Discuss the construction and necessary principle for working of a potentiometer.
(b) A battery of e.m.f. 6 volts and internal resistance 5 ohms is joined in parallel with another of e.m.f. 10 volts and internal resistancc 1 ohm and the combinitnn sends a current through an external resistance 12 ohms. Calculate current through each battery. 3
UNIT—IV
7. (a) What is a magnetic shell? Define its strength. Find an expression for the potential at any point due to a thin magnetic shell.
(b) How is a magnetic shell equivalent to a current circuit?
8. (a) State Biot-Savart Law. Using this law. calculate magnetic induction at a point on the axis of a circular coil carrying currcrit.
(b) What is the difference between a deadb eat and a ballistic galvanometer?
UNIT—V
9. (a) State Faraday’s law of electrnmagnetie induction.
(b) Obtain an expression for integral and differential form of electromagnetic induction.
10. (a) What are meant by reactance and impcdaiicw of AC circuits?
(b) Find the expression for power consumed in AC circuit. What is power factor?
4J—1000f[loH A •I4/EV1N/PHSP—2O1/357
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