Electrical and Electronics Measurement Mcq Pdf

61. The units whose size cannot be chosen independently are called

(a) absolute unit.
(b) fundamental unit.
(c) derived unit.
(d) auxiliary fundamental unit.

62. What is the prefix tera equivalent to ?

(a) 10³
(b) 10⁶
(c) 10⁹
(d) 10¹²

63. A coherent system of units is to be evolved which has N kinds of quantities to evaluate and M independent physical equations expressing relationship between them, we can independently choose the sizes of

(a) N + M quantities.
(b) N quantities.
(c) M quantities.
(d) N – M quantities.

64. Identify the one which is not a fundamental unit in SI system.

(a) Ampere.
(b) Kelvin.
(c) Metre.
(d) Joule.

65. For defining the standard metre, wavelength of which material is considered ?

(a) Neon.
(b) Krypton.
(c) Helium.
(d) Xenon.

66. What is the unit of measurement of surface / sheet resistivity ?

(a) ohm / metre.
(b) ohm-metre.
(c) ohm / sq. metre.
(d) ohm.

67. The quantity 1÷√(ε_oµ_o) in SI units has the

(a) value of 330 m/s.
(b) value 1.73 x 10⁴.
(c) dimensions LT^-1.
(d) None of the above.

68. Which of the following does not have the same units as the others? The symbols have their usual meanings.

(a) R÷L
(b) RC
(c) √(LC)
(d) 1÷√(LC)

69. If the practical units of voltage and current were each made 20 times as large as they are at present, what would be the consequent alteration in the size of the unit of capacitance ?

(a) 200 times.
(b) 60 times.
(c) 20 times
(d) nil.

70. In the SI system, the dimension of emf is

(a) ML³T^-3I
(b) ML³T^-3I^-1
(c) ML²T^-3I^-1
(d) M^-1L²T³I

71. A circuit draws a current of I when a single phase ac voltage V is applied to it. If the power factor is cosφ, then the dimensions of VIcosφ would be

(a) ML³T^-2
(b) ML²T³
(c) ML³T³
(d) ML²T^-3

72. The dimensional equation of resistance is

(a) L²MT^-2I^-4
(b) L²MT^-2I^-2
(c) L²M²T^-3I^-2
(d) L²MT^-3I^-2

73. The absolute measurement of resistance involves the measurement of

(a) length and time.
(b) length and mass.
(c) velocity.
(d) acceleration.
(e) either (a) or (c).

74. Consider the following statements. The absolute value of current can be measured by

1. dynamometer type moving coil ammeters.
2. tangent galvanometers.
3. current balance instruments.

Of these statements
(a) 1, 2 and 3 are correct.
(b) 1 and 2 are correct.
(c) 1 and 3 are correct.
(d) 2 and 3 are correct.

75. What precaution(s) is/are required for absolute measurement of current by Rayleigh current balance ?

1. Precision balance of special form must be used for the accuracy of measurement.
2. The flexible leads, used for taking current into the moving coil, must not exert appreciable torque upon the moving system.

Select the correct answer using the code given below :
(a) 1 only.
(b) 2 only.
(c) Both 1 and 2.
(d) Neither 1 nor 2.

76. The most stable primary atomic standard for frequency is

(a) hydrogen maser standard.
(b) ceasium beam standard.
(c) quartz standard.
(d) rubidium standard.

77. The modern standard of time is

(a) a second defined as 1/86,400 of a mean solar day.
(b) a second defined as time constant of an RC series circuit having R =2 MΩ, C= 500 pF.
(c) A second which is duration of 9192631770 periods of radiation corresponding to the transition between the two hyperfine levels of the fundamental state of atom cesium 133.
(d) a second defined as 1/31556925.9747 of the time required by the earth to orbit the Sun in the year 1900

78. For time and frequency, the working standard is

(a) microwave oscillator.
(b) crystal controlled oscillator.
(c) LASER.
(d) a RF oscillator.

79. Which of the following is/are primary standard(s) for voltage maintained by National Standards Laboratories ?

1 . Zener diode with 1.5 V output at 20°C.
2. Nickel cadmium rechargeable cell of 1.25 V output at 20°C

Select the correct answer using the code given below
(a) 1 only.
(b) 2 only.
(c) Both 1 and 2.
(d) Neither 1 nor 2.

80. Standard cell

(a) will have precise and accurate constant voltage when current drawn from it is few microamperes only.
(b) will have precise and accurate constant voltage when few milliamperes are drawn from it.
(c) will continue to have constant voltage irrespective of loading conditions.
(c) can supply voltages up to 10 V.