1.      When a glass rod is rubbed with silk, it _____________ a) gains electrons from silk                                        b) gives electrons to silk

c)    gains protons from silk                                         d) gives protons to silk

2. If a unit positive charge is taken from one point to another over an equipotential surface, then

a) work is done on the charge                                    b) work is done by the charge

c)    work done is constant                                           d) no work is done                                                                         

3.       Drift velocity V_d varies with intensity of electric field as per the relation

          a)                                                                     b)         

          c)                                                         d)

4.       Bio-Savart law indicates that the moving electrons (velocity v) produce a magnetic field B such

          that ________                                                             

b)   

c)    it obeys inverse cube law                                     

d) it is along the line joining the electron and point of observation.

5.        The material suitable for making electromagnetic should have

           a) high retentivity and high coercivity                        b) low retentivity and low coercivity

           c) high retentivity and low coercivity                        d) low retentivity and high coercivity

6.        Lenz’s law of electromagnetic induction is as per law of conservation of

           a) energy                                                                     b) angular momentum

           c) charge                                                                     d) electromotive force

7.        Which quantity is increased in a step-down transformer?

           a) current                                                                     b) voltage

           c) power                                                                      d) frequency

8.        The structure of solids is investigated by using

           a) Cosmic rays                                                            b) X-rays

           c)  g- rays                                                                    d) infrared rays

9.        Define electric flux. Write its SI unit.

10.      “For any charge configuration, equipotential surface through a point is normal to the electric

           field. Justify.

11.      A cell of emf ‘E’ and internal resistance ‘r’ radius a current ‘I’. Write the relation between

           terminal voltage ‘V’ in terms of ‘E’, ‘I’ and ‘r’

12.      When a charge particle moving with velocity is subjected to magnetic field the force

           acting on it is non-zero Would the particle gain any energy?

13.      What is the angle of dip at a place, where the horizontal and vertical components of the earth’s

           magnetic field are equal?

14.      Define mutual Inductance and write its S.I unit.

15.      Define “quality factor” of resonance in series LCR circuit. What is its SI unit?

16.      Which part of electromagnetic spectrum has largest penetrating power?

17.      Dielectric constant for metal ____________

18.      Force on a current carrying conductor in a magnetic field is __________

19.      Total number of magnetic lines of force crossing a surface normally is called ___________

20.      Average (or) mean value of AC over a half cycle is ____________I_o.

SECTION – B

21.      Obtain the expression for the torque experienced by an electric dipole of dipole moment in

           a uniform electric field,

22.      Derive the expression for the capacitance of a parallel plate capacitor having plate area A and

           plate separation d.

23.      Plot a graph showing temperature dependence of resistivity for a typical semiconductor. How is

           this behavior explained?

24.      An iron ring of relative permeability µ has windings of insulated copper wire of n turns per

            meter. When the current in the windings is I, find the expression for the magnetic field in the

           ring.

Or

           State Biot-Savart’s law and express this law in the vector form.

25.      Give two points to distinguish between a paramagnetic and a diamagnetic substance.

26.      State Faraday’s law of electromagnetic induction.

27.      In a Wheatstone bridge circuit, P=7W, Q=8W, R=12W and S=7W. Find the additional resistance to be used in series with ‘S’, so that the bridge is balanced.

SECTION – C

28.      Using Gauss’s law an expression for the electric field intensity at any point outside a uniformly

           charged thin spherical shell of radius R and charge density  Draw the filed lines when

           the charge density of the sphere is (i) positive, (ii) negative.

29.      a) Draw the equipotential surfaces corresponding to a uniform electric field in the z-direction.

           b) Derive an expression for the electric potential at any point along the axial line of an electric

           dipole.

30.      a) Define the term ‘conductivity’ of a metallic wire. Write its SI unit.

           b) Using the concept of free electrons in a conductor, derive the expression for the conductivity

           of a wire in terms of number density and relaxation time. Hence obtain the relation between

           current density and the applied electric field E.

Or

31.      a) State the underlying principle of a moving coil galvanometer.

           b) Give two reasons to explain why a galvanometer cannot as such be used to measure the value

           of the current in a given circuit.

          c) Define the terms: i) Voltage sensitivity and ii) Current sensitivity of a galvanometer.

Or

1. State and explain Kirchhoff’s Laws.
2. The magnetic field B due to current carrying circular loop of radius 12cm at its center is  Find the magnetic field due to this loop at a point on the axis at a distance of 5cm from the center.

32.     a) State Gauss’s law for magnetism. Explain its significance

          b) Write the four important properties of the magnetic field lines due to a bar magnet.

33.     a) Define the term ‘self-inductance’ and write its S.I. unit.

b) Obtain the expression for the mutual inductance of two long co-axial solenoids S₁ and S₂ wound one over the other, each of length L and radii r₁ and r₂ and n₁ and n₂ number of turns per unit length, when a current I is set up in the outer solenoid S₂.

34.     Draw a schematic sketch of an AC generator describing its basic elements. State briefly its

          working principle. Show a plot of variation of

1. Magnetic flux and
2. Alternating emf versus time generated by a loop of wire rotating in a magnetic field.

SECTION – D

35.     a) Use Gauss’s law to derive the expression for the electric field due to a straight

              Uniformly charged infinite line of charge density

1. Draw a graph to show the variation of E with perpendicular distance r from the line of charge.

Or

1. Describe briefly the process of transferring the charge between the two plates of a parallel plate capacitor when connected to a battery. Derive an expression for the energy stored in a capacitor.
2. A parallel plate capacitor is charged by a battery to a potential difference V. It is disconnected from battery and then connected to another uncharged capacitor of the same capacitance. Calculate the ratio of the energy stored in the combination to the initial energy on the single capacitor.

36.     a) Derive an expression for drift of electrons in a conductor. Hence deduce Ohm’s law.

b) A wire whose cross-sectional area is increasing linearly from its one end to the other, is connected across a battery of V volts. Which of the following quantities remain constant in the wire?

i) drift speed            ii) current density            iii) electric current            iv) electric field

Or

a) Obtain the expressions for current if n identical cells of internal resistance r connected in

i) Series and ii) Parallel to a load resistance R and discuss different cases related to the combination of these cells.

37.     Explain about pure inductor circuit and phase difference between current and voltage in the circuit with necessary diagram.                                                                     

Or

a) An ac source of voltage is connected to a series combination of L, C and R. Use the phasor diagram to obtain expression for impedance of the circuit and phase angel between voltage and current. Find the condition when current will be in phase with the voltage. What is the circuit in this condition called? b) In a series LR circuit X_L=R and power factor of the circuit is P₁. When capacitor with capacitance C such that X_L=X_C is put in series the power factor becomes P₂. Calculate P₁/P₂.