Basic electrical Mcq ( 61 to 80 )

61. A glass rod when rubbed with silk cloth is charged because
(a) it takes in proton
(b) its atoms are removed
(c) it gives away electrons✔
(d) it gives away positive charge

62. Whether circuit may be AC. or D.C. one, following is most effective in reducing the magnitude of the current.
(a) Reactor
(b) Capacitor
(c) Inductor
(d) Resistor✔

63. It becomes more difficult to remove
(a) any electron from the orbit
(6) first electron from the orbit
(c) second electron from the orbit
(d) third electron from the orbit✔

64. When one leg of parallel circuit is opened out the total current will
(a) reduce
(b) increase
(c) decrease✔
(d) become zero

65. In a lamp load when more than one lamp are switched on the total resistance of the load
(a) increases
(b) decreases✔
(c) remains same
(d) none of the above

66. Two lamps 100 W and 40 W are connected in series across 230 V (alternating).
Which of the following statement is correct ?
(a) 100 W lamp will glow brighter
(b) 40 W lamp will glow brighter✔
(c) Both lamps will glow equally bright
(d) 40 W lamp will fuse

67. Resistance of 220 V, 100 W lamp will be
(a) 4.84 Q
(b) 48.4 Q
(c) 484 ft✔
(d) 4840 Q

68. In the case of direct current
(a) magnitude and direction of current remains constant✔
(b) magnitude and direction of current changes with time
(c) magnitude of current changes with time
(d) magnitude of current remains constant

69. When electric current passes through a bucket full of water, lot of bubbling is observed. This suggests that the type of supply is
(a) A.C.
(b) D.C.✔
(c) any of above two
(d) none of the above

70. Resistance of carbon filament lamp as the applied voltage increases.
(a) increases
(b) decreases✔
(c) remains same
(d) none of the above

71. Bulbs in street lighting are all connected in
(a) parallel✔
(b) series
(c) series-parallel
(d) end-to-end

72. For testing appliances, the wattage of test lamp should be
(a) very low
(b) low
(c) high✔
(d) any value

73. Switching of a lamp in house produces noise in the radio. This is because switching operation produces
(a) arcs across separating contacts✔
(b) mechanical noise of high intensity
(c) both mechanical noise and arc between contacts
(d) none of the above

74. Sparking occurs when a load is switched off because the circuit has high
(a) resistance
(b) inductance✔
(c) capacitance
(d) impedance

75. Copper wire of certain length and resistance is drawn out to three times its length without change in volume, the new resistance of wire becomes
(a) 1/9 times
(b) 3 times
(e) 9 times✔
(d) unchanged

76. When resistance element of a heater fuses and then we reconnect it after removing a portion of it, the power of the heater will
(a) decrease
(b) increase✔
(c) remain constant
(d) none of the above

77. A field of force can exist only between
(a) two molecules
(b) two ions
(c) two atoms✔
(d) two metal particles

78. A substance whose molecules consist of dissimilar atoms is called
(a) semi-conductor
(b) super-conducto
(c) compound✔
(d) insulator

79. International ohm is defined in terms of the resistance of
(a) a column of mercury✔
(b) a cube of carbon
(c) a cube of copper
(d) the unit length of wire

80. Three identical resistors are first connected in parallel and then in series.
The resultant resistance of the first combination to the second will be
(a) 9 times
(b) 1/9 times✔
(c) 1/3 times
(d) 3 times