Posts Tagged ‘van de Graff’

SET OF MUST PRACTICE QUESTIONS FOR CBSE PHYSICS CLASS XII (AISSCE PHYSICS 2011)

Hello Dear Students, If you were searching for a set of questions which you cannot afford to leave while preparing for AISSCE 2011 Physics Exam, Here it is. Please practice them carefully. If you have any doubt in answering any of these questions, please feel free to ask at www.askphysics.com The content is being updated by adding more questions daily. So please come back soon for more

ELECTROSTATICS

1. State Coulomb’s law and express it in vector form
2. Derive an expression for the electric field due to a dipole at a point on its
   1. axial position and
   2. on the equatorial position.
3. State Gauss theorem of electrostatics and use it to find the electric field at a point due to
   

   1. A point charge
   2. A line of charge
   3. A plane sheet of charge
   4. A sphere of charge

4. Derive Coulomb’s law from Gauss theorem
5. Derive an expression for the torques on a dipole in a uniform electric field
6. Derive an expression for the work done in rotating a dipole in a uniform electric field
7. Derive an expression for t6he potential energy of a dipole in a unifor electric field
8. Derive an expression for the potential energy of a system of point charges
9. Describe the principle of a parallel plate capacitor
10. Derive an expression for the capacitance of a parallel plate capacitor.
11. Derive an expression for the effective capacitance when capacitors are connected in (a) parallel (b) series
12. Derive an expression for the energy stored in a parallel plate capacitor
13. Derive an expression for the electric potential due to (a) a point charge (b) a system of point charges
14. Describe the principle construction and working of Van de Graff generator

CURRENT ELECTRICITY

1. State Ohm’s law
2. Define drift velocity and derive an expression for it.
3. Derive the relation I = nAev
4. Deduce Ohm’s law
5. Explain why the resistance of a conductor increases with increase in temperature.
6. Derive expression for the effective resistance when three resistors are connected in (a) series (b) parallel
7. State Kirchhoff laws
8. What is a Wheatstone’s bridge? State its principle and deduce it using Kirchhoff laws.
9. Explain how a metre bridge is used to determine the resistance of a given wire.
10. State and explain the Principle of a potentiometer and describe the experiment to determine the internal resistance of a primary cell using potentiometer.
11. Describe how a potentiometer is used to compare the emfs of two primary cells.

To be updated soon

MAGNETIC EFFECTS OF CURRENT

1. State Biot Savart law and apply it to determine the strength of magnetic field at a point on the axis of a circular coil carrying current
2. State Ampere’s circuital law and apply it to find the magnetic field inside a solenoid and a toroid.
3. Describe the principle construction and working of a cyclotron. Why a cyclotron cannot be used to accelerate electrons
4. Derive an expression for cyclotron frequency
5. Explain the principle construction and working of a moving coil galvanometer.
6. Define the terms figure of merit and sensitivity of a galvanometer.
7. Describe how will you convert a galvanometer into (a) ammeter (b) voltmeter

To be updated soon

ELECTROMAGNETIC INDUCTION AND AC

To be uploaded soon

ELECTROMAGNETIC WAVES

1. Describe Hertz experiment to produce em waves
2. Write the properties of em waves
3. What is em spectrum? Write any 5 constituents of em spectrum in the order of increasing wavelength. Write two uses of each
4. Write Maxwell’s equations.
5. Discuss the inconsistency of Ampere’s circuital law and how it is removed in Ampere – Maxwell law.
6. What is displacement current?
7. Explain how em waves are produced?
8. Describe the transverse nature of em waves. (Show that em waves are transverse in nature)

To be uploaded soon

OPTICS

To be uploaded soon

DUAL NATURE OF MATTER AND RADIATIONS

To be uploaded soon

ATOMS AND NUCLEI

To be uploaded soon

ELECTRONIC DEVICES

To be uploaded soon

COMMUNICATION SYSTEMS

One mark questions

1. What is the meant by the term attenuation ?

2. Why ground wave transmission is restricted to 1500 kHz?

3. Define critical frequency in sky wave propagation.

4. What type of modulation is required in TV transmission?

5. Why AM radio reception is affected by electrical disturbances while FM radio reception is not?

6. What should be the length of a dipole antenna for a carrier wave of frequency 3 x 108 Hz

7. Draw a block diagram showing the basic communication system.

8. What is the range of frequencies used for FM radio transmission?

Two marks Questions

1. Distinguish analog and digital transmission

2. Write the functions of transducer and repeater in Communication systems. 3. Distinguish amplitude modulation and frequency modulation.

4. Draw a block diagram showing a simple amplitude modulator

5. Explain how a message signal is extracted from Amplitude Modulated signal.

6. Distinguish Sky wave propagation and Space wave propagation.

7. Name the different layers of earth’s atmosphere.

8. Mention two ways in which the range of transmission can be increased.

9. Explain the term modulation index and describe its significance.

10. List four devices used for communication each of which differ from other in the mode of communication.

Three marks questions

1. Explain the need for modulation

2. Derive an expression for the range of transmission from an antenna of height h.

3. Describe the demodulation of AM wave using waveforms and circuit diagrams.

VandeGraff Generator Animation

Van de Graff Generator Pics

IMPORTANT FIVE MARKS QUESTIONS FOR CLASS XII

1. Derive an expression for the Electric field at a point on the (i) axial line and (ii) equatorial line of an electric dipole
2. Describe the principle construction and working of Van de Graff Generator.
3. State Gauss’ theorem and apply it to find the electric field at a point due to
   1. A point charge
   2. A line of charge
   3. A plane sheet of charge
   4. A charged spherical conducting shell
4. Derive expression for the potential energy of a system of point charges.
5. Derive expression for the torque on a dipole in a uniform electric field.
6. Derive expression for the work done in turning a dipole in a uniform electric field.
7. Derive an expression for the potential energy of a dipole in a uniform electric field.
8. Explain the principle of a parallel plate capacitor
9. Derive an expression for the capacitance of a parallel plate capacitor.

10.  Derive an expression for the effective capacitance when three capacitors are connected in (i) series (ii) parallel

11.  Derive an expression for the energy stored in a parallel plate capacitor.

12.  Derive an expression for the loss of energy when two conductors at different potentials are brought into electrical contact. Account for this energy.

13.  Derive and expression for the energy density of a parallel plate capacitor.

14.  Derive I = nAeV_d

15.  Define drift velocity and derive an expression for it.

16.  Deduce Ohm’s law from elementary concepts.

17.  State Biot Savart’s Law and apply it to find the magnetic field at a point due to long straight conductor carrying current

18.  State Ampere’s circuital theorem and apply it to find the magnetic field inside a (i) solenoid (ii) toroid

19.  State the Principle of a potentiometer and Explain how is it used (i) to determine the internal resistance of a primary cell (ii) to compare the emfs of two primary cells

20.  State Kirchhoff’s laws and apply it to derive Wheatstone’s bridge principle.

21.  Explain how will you use a metre bridge to find the resistance of a given resistor wire?

22.  Describe the elements of earth’s magnetic field.

23.  Compare the properties of para dia and ferromagnetic substances.

24.  Derive an expression for the effective resistance  when three resistors  are connected in (i) series (ii) parallel

25.  Describe the principle construction and working of CYCLOTRON. Derive an expression for cyclotron frequency. Why electrons cannot be accelerated in a cyclotron?

26.  Derive an expression for the force between two straight long parallel conductors carrying constant current and hence define one ampere.

27.  Describe the principle construction and working of Moving Coil Galvanometer.

28.  Derive an expression for the torque on a current carrying loop kept in a uniform magnetic field

29.  Explain how will you convert a galvanometer into (i) an ammeter (ii) a voltmeter

30.  Define motional emf and derive an expression for it.

31.  What are eddy currents? Explain its applications

32.  What is self induction and self inductance? Derive an expression for the self inductance of a long solenoid carrying current

33.  Define mutual induction and mutual inductance. Derive an expression for the mutual inductance of a pair of solenoids. What are the factors affecting the mutual inductance of a pair of solenoids?

34.  Derive an expression for the average value of ac for a half cycle.

35.  Derive an expression for the RMS  value of ac

36.  Explain the principle and construction of a transformer and the various losses in a transformer.

37.  Derive an expression for impedance of a series LCR circuit. Define resonance is series LCR circuit and derive an expression for resonant frequency.

38.  Derive an expression for average power in an AC circuit. Define power factor and show that the average power consumed in a pure inductor or a pure capacitor is zero.

39.  Define Q factor of resonance. Derive an expression for Q factor.

40.  Derive lens makers formula

41.  Derive mirror formula

42.  Derive a relation connecting object distance and image distance when a point object kept in from of a convex refracting surface forms a real image inside the denser medium. (Also practice other similar cases for real images and virtual images as well as for convex interface and concave interface)

43.  Derive an expression relating angle of prism, angle of incidence, angle of emergence and angle of deviation when light is refracted by a prism

44.   Derive n = sin (A+D)/2 / sin (A/2) for refraction through a prism.

45.  Derive an expression for the effective focal length of the combination of two lenses in contact.