Possible Three mark Questions


1.      In which fields the property of attraction and repulsion between charged bodies is used ?

2.      Distinguish between conductors and insulators.

3.      What is an electric dipole ? Give the unit of the dipole moment.

4.      What is an electric line of force ?

5.      State Gauss’s law.

6.      What is an equipotential surface ?

7.      Define the electric flux. Give its unit.

8.      Why it is safer to be inside a car than standing under a tree during a lightning ?

9.      Give the uses of the capacitors.

10.  What is a polar molecule ? Give two examples.

11.  Two charges 10 X 10 -9 μC and 20 X 10 -9 μC are at a distance 0.03 m. Calculate the electric potential energy.

12.  What is action of points ?

13.  In the given diagram, calculate the effective capacitance between A and B.

14.  State Ohm’s law.

15.  Define resistivity of a material.

16.  Give the applications of the secondary cells.

17.  What is the value of the red, red, red coloured carbon resistor with no ring on the other side of the resistor ?

18.  Give any three uses of super conductors.

19.  Distinguish between electric power and electric energy.

20.  What is a wattmeter ?

21.  Define: Peltier coefficient and give its unit.

22.  Define: Maxwell’s right hand cork screw rule.

23.  Define: ampere.

24.  Write a short notes on current sensitivity of a galvanometer.

25.  How will you convert a galvanometer into an ammeter ?

26.  What is Lorentz force? Give any two properties.

27.  In a TG the deflection is 30o for a current of 1A. Calculate the current that produces a deflection of 60o.

28.  State Biot-Savart law.

29.  Define: Thomson effect.

30.  Calculate the resistance of the tungsten wire of a 100W, 220V bulb.

31.  The magnetic induction at a point 10 cm from a long straight current carrying conductor is 4 X 10 -6 tesla.

32.  Calculate the current in the conductor.

33.  What are the limitations of a cyclotron?

34.  State Lenz’s law.

35.  State Flemings right hand rule.

36.  What is self induction ?

37.  Define : the unit of coefficient of mutual inductance.

38.  Define : the efficiency of a transformer.

39.  Define : the rms value of an AC.

40.  Define : Q factor. 8. Calculate the mutual inductance between two coils when a current of 3A changing to 8A in 0.5s in one coil, induces an emf of 50V in the other coil.

41.  What are Fraunhofer lines ?

42.  What is Tyndal effect ?

43.  Define: wavefront.

44.  State Huygen’s principle.

45.  Give the differences between uniaxial and biaxial crystals.

46.  What is polarization ?

47.  What are the uses of IR rays ?

48.  State Brewster’s law.

49.  State any five properties of canal rays .

50.  State the drawbacks of Rutherford’ s atom model.

51.  Define excitation potential energy.

52.  What are hard X-rays and soft X-rays ?

53.  State the conditions to achieve laser action ?

54.  State Moseley’s law.

55.  What is normal population ?

56.  Give the uses of laser in medicine.

57.  Calculate the minimum wavelength of X-rays produced by an X ray tube at 1000 kV.

58.  The Rydberg constant for hydrogen is1.097X10 7m -1.Calculate the shortest wavelength of Lyman series.

59.  Calculate the energy of the electron in the second orbit in the hydrogen atom.

60.  State the postulates of Bohr’s atom model.

61.  What is photo electric effect ?

62.  Define threshold frequency.

63.  Define work function of a material.

64.  What are photo electric cells ?

65.  What are de Broglie waves ?

66.  Give the uses of the electron microscope.

67.  Define a frame of reference.

68.  State the postulates of the special theory of relativity.

69.  The rest mass of an electron is 9.1X10 -31 kg.What will be its mass if it moves with (4/5) th of the velocity of light.

70.  The work function of iron is 4.7 eV. Calculate the threshold frequency.

71.  Calculate the rest energy of an electron in MeV.

72.  State the limitations of using an electron microscope.

73.  Define radioactivity.

74.  Define one curie.

75.  What is artificial radioactivity ?

76.  Explain the types of neutrons.

77.  What is a breeder reactor ?

78.  What is artificial transmutation of elements ?  

79.  What are cosmic rays ?

80.  Name the types of quarks. How a proton can be represented by quarks ?

81.  Calculate the nuclear radius of 13 Al 27 .

82.  Tritium has a half life period of 12.5 years. What fraction of the sample will be left over after 25 years ?

83.  The decay constant of a radioactive sample is 0.00231 / day. Calculate the half life and mean life periods.

84.  The isotope of 92 U 238 successively undergoes three α - decays and two β -decays. What is the resulting isotope ?

85.  What is meant by depletion region of PN junction diode ?

86.  What are the biasing conditions to be followed in normal operation of a transistor ?

87.  What is an amplifier ? Mention its properties.

88.  In a common base transistor circuit I C = 0.97 mA and I B = 30 μA. Calculate the value of α .

89.  What are sinusoidal and non-sinusoidal oscillators ?

90.  State Barkhausen conditions for oscillators.

91.  Determine the frequency of oscillations in a Colpitt’s oscillator, if C1 = 0.01 μ F, C2 = 0.03 μ F and L = 100 mH.

92.  What is an integrated circuit ?

93.  Distinguish between analog and digital signals.

94.  Draw a circuit of OR gate using diodes.

95.  What are universal gates ? Why they are called so ?

96.  Prove the Boolean equation ( A + B ) ( A + C ) = A + BC .

97.  What is called skip zone ?

98.  Define modulation factor.

99.  What is an antenna ?

100.   Define: phase modulation.

101.   Define: bandwidth.

102.   What is directivity of an antenna ?

103.   What is called Buffer ?

104.   What is meant by scanning ?

105.   What are the applications of radar?

106.   What is meant by MODEM ?

107.   What are the advantages of fiber optic communication system ?

108.   What are advantages of frequency modulation ?