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** Old Papers**

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**Physics **

AIOU |

### ALLMA IQBAL OPEN UNIVERSITY

Level Bachelor Code : 3404 Semester Spring 2011**Note:**ATTEMPT ANY FIVE QUESTIONS .ALL CARRY

EQUAL MARKS

Questions #1

a) Calculate the electric field due to an electric dipole.

b) A molecule of water vapor causes an electric field in the

surrounding space as if it were an electric dipole like that

of figure below. Its dipole moment has a magnitude

P = 6.2 x 1030cm.what is the magnitude of electric field at a

distance z =1.1 nm from the molecule on its dipole axis?

Question #2 (20)

Discuss Gauss’s Law and apply it on

i) Cylindrical symmetry

ii) Planar symmetry

iii) Spherical symmetry.

Question #3

a) Give a complete account on electric potential energy, calculate

potential due to an electric dipole?

b) The potential at the centre of a uniformly charged circular disk

of radius R = 3.5cm is Vo = 550V.

i) What is the total charge q on the disk?

ii) What is the potential at a point on the axis of the disk at a

distance z = 5 OR from the centre of the disk?

a) Discuss Ohm’s law in detail. Define electric current also.

b) One end of an aluminium wire whose diameter is 2.5mm is

welded to one end of a copper wire whose diameter is 1.88mm.

the composite wire carries a steady current i of 17 mA.

what is the current density in each wire?

a) Calculate the field due to the current interaction of magnetic

field with current.

b) Explain Biot Savart Law.

a) Calculate the magnetic fields of a solenoid .Also calculate the

magnetic field of a toroid.

b) What is thermo electrical seedback?

a) What is Pelter’s and ThomsoB. effeet? Calcu!ate total EMF in

thermocouple.

b) What is Faraday’s law of electromagnetic induction and it's

differential from?

a) Calculate power in alternating current circuits

b) A series RLC circuit driven with £rms = 120V at frequency

fd = 60.0 Hz contains a resistance R=200 Ohm an iinductance with

Xl = 80.0 Ohm and capacitance with Xc = 150 Ohm.

i) What are the power factor cos ф and phase constant ф of the

circuits

ii) What is the average rate Pav at which energy is dissipated

in the resistance.

##
**Old Papers**

###
**Physics **

AIOU |

### ALLMA IQBAL OPEN UNIVERSITY

Level Bachelor Code : 3404 Semester Autum 2011**Note:**ATTEMPT ANY FIVE QUESTIONS .ALL CARRY

EQUAL MARKS

Q 1. a) Describe Coulomb’s law and its gravitational law. What

are the differences between both laws?

b) A particle of charge -q, is located at the origin of an x-axis

at what location should a second particle of charge -4qi be

placed so that the net electric field of two particles is zero

at x = 3.0mm. [10]

Q2.a) Define and explain the flux of an

electric field. [10] b) A Gaussian surface in the form of a

cylinder of radius R is immersed in a uniform electric

field E. with the Cylinder axis parallel to the field .What

is the flux cp of the electric field through this closed

surface.

Q3.a) Describe scries RLC circuit and derive the expression for

e.m.f. developed across each component and the impedance

of the circuit. C \ b) Define resonance frequency and derive

the expression

Q4. a) Explain the relationship between the current and voltage

b) Write Biot Savarfs Law

Q5. Analyze tlhe travelling electromagnetic wave quantitatively

and qualitatively.

Q 6.

a) Explain the diamagnetic, paramagnetic and fciTOtbagmitic

behavior in matter,

b) Explain hysteresis curve and its practical application.

Q7. Write note on any two of the following.

i) Faraday's law

ii) Mutual Induction

iii) Ampere's law

Q:8

(a) Derive the expression for field build up due to solenoid

and toroid

b) Why magnetization vector "M' lags behind magnetic intensity

vector ‘H’? Expalin.

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