CURRENT ELECTRICITY PART 7

CURRENT ELECTRICITY PART 7

61.  A 40 Watt bulb is connected in series with room heater if Now 40 watt bulb is replaced placed by 100 Watt bulb, the heater output will

a. increase. 

b.Decrease

c. remains same. 

d.Heater will burn out.

62. A 50 Watt 220 volt bulb is supplied with 110 volt power consumption by the bulb will be 

a.slightly less than 125 watt

b. slightly greater than 125 what 

c.exactly 125 watt

d. 250 watt

63. In an electric kettle water boils in 10 minutes it is required to boil the water in 15 minutes using same supply mains 

a.length of heating element should be decreased

b.  length of heating element should be inceased 

c. length of heating element has no effect on heating of water 

d. of the above

64. An electric filament bulb can be worked from

a.  DC supply only 

b. AC supply only 

c. battery supply only

d.  all of the above

65. Resistance of a tungsten lamp................ as applied voltage increases 

a. Increases

b. Decreases

c. remain same 

d.none of the above

66. Electric current passing through the circuit produces 

a. magnetic effect

b. Luminous effect

c.  thermal effect 

d.chemical effect

e. all of the effects

67. Resistance of a material always decreases If 

a. temperature of material is decreased

b. temperature of material is increased

c. number of free electrons available becomes more 

d. none of the above is correct

68. If the efficiency of machine is to be high what should be low 

a. Input  power 

b. losses 

c.true component of power

d. kwh consumed

e.  ratio of output to input

69. When electric current passes through a metallic conductor with temperature rises this is due to 

a.collisions between conduction electrons and atoms

b.  the release of conduction electrons from parent atoms 

c. mutual collision between metal atoms

d. mutual collisions between conducting and electrons

70. Two bulbs of 100 W and 200 W rated at 250 V will have resistance ratio as

a. 4 : 25

b. 25 : 4

c. 2 : 5

d. 5 : 2

ANSWERS

61.b, 62.b, 63.a, 64.d, 65.b, 66.e, 67.c, 68.b, 69.a, 70.c

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