INDEXSl No.

Chapter Page no.

UNIT –I (ELECTROSTATICS) 2

1 ELECTRIC CHARGE AND COULOMB’S LAW 3

2 Electric Field and Electric Dipole 5

3 ELECTRIC POTENTIAL 8

4 GAUSS’S LAW 12

5 CAPACITORS 14

6 UNIT-II (CURRENT ELECTRICITY): 22

7 HEATING EFFECT OF CURRENT 27

8 UNIT-III (MAGNETIC EFFECTS OF CURRENT & MAGNETISM): 33

9 MAGNETIC FIELD DUE TO CURRENT 33

10 MOTION OF CHARGED PARTICLES IN ELECTRIC AND MAGNETIC FIELDS 39

11 MAGNETISM 45

12 UNIT-IV (EMI &A.C): 54

13 ALTERNATING CURRENTS 64

14 LCR CIRCUIT 74

UNIT-V (E.M. Waves): 80

15 UNIT-VI (OPTICS): 87

16 REFRACTION OF LIGHT 95

17DISPERSION

99

18 OPTICAL INSTRUMENTS 101

19 DIFFRACTION 114

20 POLARISATION: 115

21 UNIT- VII (DUAL NATURE OF MATTER AND RADIATION): 123

22 UNIT-VIII (ATOMS AND NUCLEI): 125

23 UNIT- IX (ELECTRONICS): 127

24 UNIT- X (COMMUNICATION SYSTEM): 129

MPORTANT TOPICS/CONCEPTS UNITWISE

UNIT-I (ELECTROSTATICS):

1. Definition and unit of electric field intensity2. Electric dipole – Definition and unit of electric dipole moment, electric field at axial and equitorial line,

torque and potential energy/work done3. Gauss law and its applications 4. Equipotential surfaces5. Capacitance – definition and unit, capacitance of a parallel plate capacitor with dielectric medium between

the plates, energy stored /energy density and energy in case of series/parallel combinations of capacitors.6. Electric field lines-sketch (i) q<0, (ii) q>0, (iii) for a system of two equal and opposite charges, (iv) for a

system of similar charges & properties of field lines.7. Van-de-Graff Generator

SYNOPSIS

Electric charges and Coulomb’slaw

II Electric Field and Electric Dipole

III ELECTRIC POTENTIAL

IV . GAUSS’S LAW

V. CAPACITORS

PREVIOUS YEAR QUESTIONS

1. If the radius of the Gaussian surface enclosing a charge is halved , how does the electric flux through the Gaussian surface change? 1M

A. Electric flux is independent of the radius . Electric flux remains constant.2. Define the term electric dipole moment of a dipole. State its S.I. Unit. 1M

A. It is defined as the product of either charge and the length of electric dipole P = q X 2a . It is a vector quantity whose direction from negative to positive charge.

3. Which orientation of an electric dipole in a uniform electric field would correspond to

stable equilibrium.? A. When the electric dipole is in the direction of the electric field, the

4. Two point charges 20 X 10-6 C and -4 X 10-6 C are separated by a distance of 50cm in air.(i) Find the point on the line joining the charges , where the electric potential is zero.?(ii) Also find the electrostatic potential energy of the system.2M

5. Two point charges 4Q, Q are separated by 1m in air. At what point on the line joining the charges is the electric field intensity zero?Also calculate the electrostatic potential energy of the system of charges, taking the value of charge, Q = 2 X 10-7C. 2M

6. Two point charges C and -2C are separated by a distance of 1m in air. Calculate at what point on the line joining the two charges is the electric potential zero. 2M

7. The electric field and electric potential at any point due to a point charge kept in air is 20N/C and 10 V respectively. Compute the magnitude of this charge.

2M8. The given graph shows the variation of charge q Vs potential difference V for two

capacitors C1 and C2 . The two capacitors have same plate separation but the plate area of C2 is double than that of C1. Which of the lines in the graph correspond to C1 and C2 and

why? 2M 9. Two capacitors of capacitance 6F and 12F are connected in series with a battery. The

voltage across the 6F capacitor is 2V. Compute the total battery voltage.2M

10. A parallel capacitor with air between the plates has a capacitance of 8pF. The separation between the plates is now reduced by half and the space between them is filled with a medium of dielectric constant 5. Calculate the value of capacitance of the capacitor in the second case.2M

11. A point charge ‘q’ is placed at O as shown in the figure. Is Vp-Vq positive or negative when (i) q > 0 (ii) q < 0 ? Justify your answer.2M

12. The electric field E due to a point charge at any point near it is defined as E=lim q 0 where q is the rest charge and F is the force acting on

it.What is the physical significance of lim q tends to 0 in this expression? Draw the electric field lines of a point charge Q when (i)Q>0 (ii) Q<0. 2m

13. Define electric flux . Write its S.I. units. A spherical rubber balloon carries a charge that is uniformly distributed over its surface. As the balloon is blown up and increases in size, how does the total electric flux coming out of the surface charge ? Give reason. 2M

14. State Gauss’s theorem in electrostatics. Apply this theorem to derive an expression for electric field intensity at a point near an infinitely long straight charged wire. 3M

15. Explain the underlying principle of working of a parallel plate capacitor. If two similar plates, each of area A having surface charge densities + and - are separated by a distance d in air, write expression for

(i) the electric field at points between the two plates.(ii) The potential difference between the plates.(iii) The capacitance of the capacitor so formed. 3M

16.Using Gauss’s theorem, show mathematically that for any point outside the shell, the field due to a uniformly charged thin spherical shell is the same as if the entire charge of the shell is concentrated at the centre. Why do you expect the electric field inside the shell to be zero according to this theorem? 3M

17. Deduce an expression for the electric potential due to an electric dipole at any point on its axis. Mention one contrasting feature of electric potential of a dipole at a point as compared to that due to a single charge. 3M

18. What is electric flux? Write its SI units. Using Gauss’s theorem, deduce an expression for the electric field at a point due to a uniformly charged infinite plane sheet. 3M

19. State Gauss’s theorem in electrostatics. Apply this theorem to derive an expression for electric field intensity at a point outside a uniformly charged thin spherical shell.

20. Derive an expression for the energy stored in a parallel plate capacitor.On charging a parallel plate capacitor to a potential V, the spacing between the plates is halved, and a dielectric medium of r = 10 is introduced between the plates, without disconnecting the d.c. source. Explain, using suitable expressions, how the (i) capacitance ,(ii) electric field and (iii) energy density of the capacitor change.5M

21. (a)Define electric flux. Write its S.I.units(b) The electric field components due to a charge inside the cube of side 0.1 m are as shown.

Ex = x, where = 500 N/Cm Ey= 0 , Ez=0.

Calculate (i) the flux through the cube , and (ii) the charge inside the cube.

IMPORTANT QUESTIONS:1. Name & define a physical quantity whose S.I. unit is C/V. 2. A glass rod acquires a charge of +3.2 x 10 -4 C when it is rubbed with silk . How many electrons are transferred from glass rod to silk. How much would be the charge acquired by silk? Is their any transfer of mass from glass rod to silk .3. How does the separation between two point charges reduce when force between them becomes double ?

4. (i) Sketch electric lines of force for (a) q<0 & (b) q>0 (ii) Draw equi potential surfaces for a field that uniformly increases in magnitude but remains along Z-direction. (iii A point change ‘q’ in placed at ‘O’ as shown in the figure. O P Q VP – VQ is positive or negative when (i) q > o and (ii) q < o ? q

5. A system has two charges qA = 2.5 x 10-7C and qB = - 2.5 x 10 -7C, located at points A(0,0, -15) & B(0,0, +15) respectively. What is the total charge & electric dipole moment of the system? 6. A uniform electric field of 300N/C is directed along -X axis . A, B & C are three points in the field, having x and y coordinates(in metre), as shown in figure. Find the work done in moving a charge of 1C from (i) A to B & (ii) A to C. Among points B & C, which one is at higher potential?

UNIT-II (CURRENT ELECTRICITY):

1. Numerical based on Ohm’s law and series/parallel law of resistors.2. Resistivity – Definition and unit , concept of drift velocity and its relation with average relaxation time,

expression for resistivity in terms of average relaxation time.3. Kirchhoff’s laws and their applications4. Balanced condition for Wheat Stone Bridge 5. Meter Bridge and its application to determine unknown resistance and hence resistivity.6. Potentiometer and its application to compare the emfs and to determine internal resistance of a primary

cell.

S Y N O P S I S

B(4,4)C(-3,4)

XO

A(4,1)

Y

HEATING EFFECT OF CURRENT

PREVIOUS YEAR QUESTIONS

1. Sketch the graph showing the variation of resistivity of carbon with temperature.

1M

2. Write the mathematical relation between mobility and drift velocity of charge

carriers in a conductor. Name the mobile charge carriers responsible for conduction

of electric current. 1M

2. The variation of potential difference V with length l in case of two potentiometers P

and Q is as shown. Which one of these two will you prefer for comparing emf’s of

two primary cells? 2M

3. You are given ‘n’ resistors , each of resistance ‘r’ . These are first connected to get

minimum possible resistance. In the second case, these again connected differently

to get maximum possible resistance. Compute the ratio between the minimum and

maximum values of resistances obtained. 2M

4. Draw a circuit diagram using a meter bridge and write the necessary mathematical

relation used to determine the value of an unknown resistance. Why can not such an

arrangement be used for measuring very low resistance. 2M

5. Two cells E1 and E2 in the given circuit diagram have an emf of 5V and 9V and

internal resistance of 0.3 and 1.2 respectively. Calculate the value of current

flowing through the resistance of 3.

6. Two metallic wires of the same material have the same length but cross-sectional

area is in the ratio 1:2. They are connected (i) in series and (ii) parallel. Compare the

drift velocities of electrons in the two wires in both the cases (i) and (ii).

7. (i)Calculate the equivalent resistances of the given electrical network between the

points A and B.

(ii) Also calculate the current through CD and ACB , if a 10 V d.c. source is

connected between A and B, and the value of R is assumed as 2.

3M

8. A cylindrical metallic wire is stretched to increase its length by 5%. Calculate the

percentage change in its resistance.

9. Write the mathematical relation for the resistivity of a material in terms of relaxation

time,number density and mass and charge carriers in it. Explain, using the relation,

why the resisitivity of a metal increases and that of a semiconductor decreases with

rise in temperature.

10.For the potentiometer circuit shown in the given figure, points X and Y represents

the two terminals of an unknown emf E’ . A student observed that hen the jockey is

moved from the end A to the end B of the potentiometer wire, the deflection in the

galvanometer remains in the same direction. What may be the two possible faults in

the circuit that could result in this observation? If the galvanometer deflection at the

end B is (i) is more (ii) less, than that at the end A, which of the two faults, listed

above, would be there in the circuit? Give reason in support of your answer in each

case.

A. (a)Two possible faults are (i) the emf applied across AB is less than the unknown

emf. (ii) –ve terminal of the source of unknown emf is joined with end A of the wire.

(b) The galvanometer deflections at the end B is more means source of unknown emf

have beeen joined with its negative terminal to end A. Current gets divided at point

A and combines at point B.The galvanometer deflection at the end B is less than at

the end A means theemf applied is less than the unknown emf used. Currents get

combined at end A and divided at end B.

11.A 10 m long wire of uniform cross-section of 20 resistance is fitted on the board. The wire is connected in series with a battery of 5V along with an external resistance of 480. If an unknown e.m.f. E is balanced at 600 cm of this wire, calculate (i) the potential gradient of wire, (ii) value of unknown e.m.f.

IMPORTANT QUESTIONS:1. A current of 2 m A is passed through a colour coded resister with first,second and third rings of yellow, green and orange colours. What is the voltage drop across the resister? Neglect the tolrrance.

2 Define the term ‘potential gradient’. Using this concept, explain the method of comparision of e.m.fs. of two primary cells using a potentiometer. Write two possible causes of potentiometer giving only one sided deflection.

3. How will you determine the specific resistance of a given wire in your laboratory? 4 A wire of uniform area of cross-section & length ‘l’ has a resistance of 16Ω. It is cut in to four equal parts. Each part is stretched uniformly to length ‘l’ & all four stretched parts are connected in parallel. Calculate equivalent resistance. 5 (a) A p.d. ‘V’ is applied to conductor of length ‘L’ & diameter ‘D’. How are the

electric field & resistance of the conductor affected when in turn (i) ‘V’is halved (ii) ‘L’ is doubled (iii) ‘D’ is halved,where in each case ,the other two factors remain the same. (b) Write the nature of the path of electrons (i) in the presence of electric field (ii) in the absence of electric field (c) What happens to the drift velocity of electrons & resistance, if length of the conductor is doubled (keeping p. d. unchanged)? 6. Two cells of e.m.fs. 1.5 V & 2 V and internal resistances 1Ω & 2Ω respectively are connected in parallel so as to send current in the same direction through an external resistor of 5Ω. (a) Draw the circuit diagrame. (b) Using Kirchhoff’s laws , calculate (i) current through each branch of the circuit. (ii) p. d. across 5Ω resistance

7 A series combination of 2kΩ resistor and a 1 kΩ resistor is connected across a battery of emf 6V and negligible internal resistance. The potential drop across the 2 kΩ resistor is measured using a 1 kΩ voltmeter. Find the reading shown by the voltmeter.

UNIT-III (MAGNETIC EFFECTS OF CURRENT & MAGNETISM):

1. Statement of Biot Savart’s law and its application to determine magnetic field due to a current carrying circular coil .

2. Concepts of force on a moving charge and force on a current carrying conductor placed in uniform magnetic field.

3. Force experienced by two straight current carrying parallel conductors 4. Concept of torque on a current carrying coil and its application to M.C.G (sensitivity and conversion of

M.C.G to voltmeter and ammeter)5. Cyclotron and its limitations to accelerate light charged particles such as electrons.6. Ampere’s circuital law and its applications7. Magnetic dipole- definition and unit of magnetic dipole moment ,torque and work done /potential energy8. Magnetic elements 9. Properties of Dia, Para ,Ferro magnetic substance with reference to permeability, susceptibility, Curie law

and their behavior in uniform magnetic field.10. Concept of Hysteresis – retentivity / coercivity and temporary/permanent magnets.

SYNOPSISI . MAGNETIC FIELD DUE TO CURRENT

X