## Question Bank in Physics Class XII

The collection will also be helpful for students of other syllabuses.

The file consists of syllabus, key points, collection of very short Answer (1 mark), Short answer type question – solved (2 marks), short answers (3 marks), Long answers (5 marks), Solved numericals and 3 sample papers.

The contents are arranged chapter-wise. Any student will find this a boon for easy preparation and to score better marks in Physics.

## CBSE Physics Solved Board Question Papers 2008, 2009, 2010 & 2011 – All versions

Download CBSE Physics Solved Board Question Papers 2008, 2009, 2010 & 2011 – All versions (Delhi, Outside Delhi & Foreign)

The question Papers are in PDF format, all question papers with solution in a single file. So, it may take some time for the download to finish.

CBSE Physics Class 12 Board Question Papers 2008 to 2011 all sets (SETS I, II & III) and versions (DELHI, FOREIGN, OUTSIDE DELHI)

## Quick Revision for Class X Physics SA1

CHAPTER -12 ELECTRICITY

GIST OF THE LESSON

1. Positive and negative charges: The charge acquired by a glass rod when rubbed with silk is called positive charge and the charge acquired by an ebonite rod when rubbed with wool is called negative charge.
2. Coulomb: It is the S.I. unit of charge. One coulomb is defined as that amount of charge which repels an equal and similar charge with a force of 9 x 109 N when placed in vacuum at a distance of 1 meter from it. Charge on an electron = -1.6 x 10-19 coulomb.
3. Static and current electricities: Static electricity deals with the electric charges at rest while the current electricity deals with the electric charges in motion.
4. Conductor: A substance which allows passage of electric charges through it easily is called a ‘conductor’. A conductor offers very low resistance to the flow of current. For example copper, silver, aluminium etc.
5. Insulator: A substance that has infinitely high resistance does not allow electric current to flow through it. It is called an ‘insulator’. For example rubber, glass, plastic, ebonite etc.
6. Electric current: The flow of electric charges across a cross-section of a conductor constitutes an electric current. It is defined as the rate of flow of the electric charge through any section of a conductor.

Electric current = Charge/Time     or        I = Q/t

Electric current is a scalar quantity.

1. Ampere: It is the S.I. unit of current. If one coulomb of charge flows through any section of a conductor in one second, then current through it is said to be one ampere.                                                                                                                         1 ampere = 1 coulomb/1 second    or      1 A = 1C/1s = 1Cs-1                                                                                                                                                                                                              1 milliampere =    1 mA = 10-3 A                                                                                                                                                                                 1 microampere = 1µA = 10-6 A
2. Electric circuit: The closed path along which electric current flows is called an ‘electric circuit’.
3. Conventional current: Conventionally, the direction of motion of positive charges is taken as the direction of current. The direction of conventional current is opposite to that of the negatively charged electrons.
4. Electric field: It is the region around a charged body within which its influence can be experienced. Continue reading “Quick Revision for Class X Physics SA1”

## Summative Assessment 1 (SA1) Sample Papers for class 9 Physics

The Summative Assessment 1 is about to begin. As per request from student from various parts of India and abroad, we are publishing some solved sample papers in Physics, which we think, would help you in scoring better marks in the forthcoming SA1 exams.

(Based on Motion)

Class 9 Physics Sample Paper 1  Solved

Class 9 Physics Sample Paper 2  Solved

## Must Practice Questions for CBSE Physics CLASS 12: Solved

We will publish here the portions one cannot afford to miss while preparing for the CBSE class 12  Physics Examination

The Chapters will be posted below. On Clicking the name of the chapter a new page will open. On that page there will be a set of collected questions. On clicking the questions, the complete solution to the questions will open.

Please note that this system is under preparation. We hope to complete this within a month. The link will be activated only after completing the project.

## A too simple question paper from Physics (Magnetic effects of current and magnetism) for class XII

If you find these question easy to answer, well and good. If you don’t, please revise these portions thoroughly. These are based on just the minimum level of learning expected from a Class XII student.

1. State Gauss theorem in magnetism.
2. Define the terms retentivity and coercivity.
3. Which direction will a magnetic compass show when it is kept horizontally at the magnetic north pole of earth?
4. Determine the magnitude and direction of magnetic field to be applied in a region with a vertical electric field 1000 V/m (downwards) where a proton has to move towards east with a speed of 100 m/s without any deflection. (Disregard the presence of earth’s magnetic field.)
5. Derive expression for the force on a current carrying conductor in a uniform magnetic field.
6. Using Ampere’s circuital law, derive an expression for the magnetic field at a point due to a straight conductor carrying current.
7. The radius of the first electron orbit of a hydrogen atom is 0.5 A. The electron moves in this orbit with a uniform speed of 2.2 x 106 m/s. What is the magnetic field produced at the centre of the nucleus due to the motion of this elecetron?
8. Derive the relation mr = 1+cm (relation between magnetic permeability and magnetic susceptibility)
9. Mention the magnetic elements of earth and define each.
10. Derive expression for the magnetic dipole moment of a revolving electron.
11. Describe the principle, construction and working of a cyclotron. Why electrons cannot be accelerated using a cyclotron?

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1. Gauss theorem in magnetism states that closed surface integral of magnetic field in a closed surface is zero. That is, the net magnetic flux through a closed surface is always zero.  Mathematically,
2. Retentivity is the magnetization retained by a specimen when the magnetizing field is zero. Coercivity is the reverse magnetizing force required to completely demagnetize and specimen.
3. The compass needle will not show any particular direction as the horizontal component is zero at the magnetic poles. It can rest in any direction in which it is placed just like a non-magnetic needle.

## Communication Systems : Physics Revision Test for Class XII CBSE

COMMUNICATION SYSTEMS

Max. Marks :: 30 Time:: 75 minutes

1 mark questions

1. Define bandwidth of a signal.
2. Define modulation index.
3. What is the function of a modem?
4. Why is short wave band used for long distance transmission?
5. Name the type of modulation prefered for digital communication.
6. Draw diagram to represent a digital signal and an analogue signal.
7. What do you mean by sampling of signal?
8. Name the appropriate communication channel needed to send a signal of band width 100 kHz over a distance of 8 km.2 Marks Questions
9. Derive an expression for the maximum distance up to which TV signals can be transmitted using a transmitting antenna of height h.
10. Distinguish amplitude modulation and amplitude modulation.
11. Draw a block diagram of a simple amplitude modulation system and explain briefly how amplitude modulation is achieved.
12. What is the need for modulating a message signal for long distance transmission?3 marks questions
13. 5 Marks Questions

To be Updated Soon. Visit Again at the earliest

# Magnetic Effects of Current and Magnetism

Max. Marks :: 30 Time:: 75 minutes

1 mark questions

1. State the Principle of a cyclotron
2. Calculate the range of an ammeter of resistance 24 ohms and can allow a maximum current of 500mA through its coil, when shunted by a resistance of 3 ohms.
3. Write the dimensional formula of μ0
4. Define 1 ampere as defined in SI (based on force between two straight parallel conductors of infinite length)
5. State Fleming’s left hand rule.
6. State the principle of a moving coil galvanometer
7. Why a cyclotron cannot be used to accelerate electrons.
8. Write the resistance of (a) an ideal ammeter (b) an ideal voltmeter.

2 Marks Questions

9. Derive an expression for cyclotron frequency.
10. Write the difference between paramagnetism and ferromagnetism
11. State the factors affecting the strength of an electromagnet.
12. Calculate the magnetic moment of the electron in the ground state of hydrogen atom.

3 marks questions

13. State Ampere’s circuital law and apply it to find the magnetic field inside a torroid.
14. Discuss the equivalence of a bar magnet and a current carrying solenoid.
15. What are the magnetic elements of earth. Define each.

5 Marks Questions

16. State Biot Savart law and apply it to find the magnetic field at a point on the axis of a circular loop carrying current.

# Current Electricity

Max. Marks :: 30 Time:: 75 minutes

1 mark questions

1. The drift velocity is of the order of a few cm/s. But when we switch on a bulb, it glows instantly. How is this possible?
2. Define internal resistance.
3. If n identical resistors are connected in series first and then in parallel, Calculate the ratio of effective resistance in series to the effective resistance in parallel.
4. Define mobility.
5. State Ohm’s law.
6. State the principle of a potentiometer.
7. Write the colour coding of a carbon resistor of resistance 18000 Ω and a tolerance 10%
8. What is a thermistor?

2 Marks Questions

9. Deduce Ohm’s law using the concept of drift velocity.
10. State Kirchhoff’s laws for electric networks.
11. Distinguish emf and terminal voltage.
12. Derive an expression for drift velocity.

3 marks questions

13. A battery om emf E and internal resistance r gives a current 0.5 A with an external resistance of 12 Ω and a current 0.25 A with an external resistance of 25Ω. Calculate the internal resistance and emf of the cell.
14. An electric motor operating on a 50 V dc supply draws a current of 12A. If the efficiency of the motor is 30%, estimate the resistance of the windings of the motor.
15. Draw the diagram showing the experimental arrangement for determining the resistance of a given wire of unknown resistance.

5 Marks Questions

16. (a)Explain how a potentiometer is used to determine the internal resistance of a primary cell.

(b)State the factors affecting the internal resistance of a cell