## electrical

### Basic Electrical Engineering MCQ Questions With Answers Page - 3

1.
 When the leg of parallel circuit is opened out the total current will be A Reduce B Increase C Decrease D Become zero Answer : C Explanation :
2.
 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 Answer : B Explanation :
3.
 Resistance of  220 V, 100 W lamp will be A 4.84 Ω B 48.4 Ω C 484 Ω D 4840 Ω Answer : C Explanation :
4.
 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 Answer : A Explanation :
5.
 When electric current passes through a bucket full of water, lot of bubbling is observed. This suggests that the type of supply is A AC B DC C Any of above two D None of the above Answer : B Explanation :
6.
 Resistance of carbon filament lamp …… as the applied voltage increases. A Increases B Decreases C Remain same D None of above Answer : B Explanation :
7.
 Bulbs in street lighting are all connected in A Parallel B Series C Series-parallel D End-to-end Answer : A Explanation :
8.
 For testing appliances, the wattage of test lamp should be A very low B low C high D any value Answer : C Explanation :
9.
 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 Answer : A Explanation :
10.
 Sparking occurs when a load is switched off because the circuit has high A Resistance B Inductance C Capacitance D Impedance Answer : B Explanation :
11.
 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 C 9 times D Unchanged Answer : C Explanation :
12.
 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 Answer : B Explanation :
13.
 A field of force can be exist between A Two molecule B Two ions C Two atoms D Two metal particles Answer : B Explanation :
14.
 A substance whose molecules consists dissimilar atom is called A Semi-conductor B Super-conductor C Compound D  Insulator Answer : C Explanation :
15.
 A microvolt is A 1 × 10-3 V B 1 × 10-4 V C 1 × 10-5 V D 1 × 10-6 V Answer : D Explanation :
16.
 Which of the following could be the value of resistivity of copper? A 1.72 × 10-4 Ω-m B 1.72 × 10-5 Ω-m C 1.72 × 10-6 Ω-m D 1.72 × 10-8 Ω-m Answer : D Explanation :
17.
 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 Answer : A Explanation :
18.
 Three identical resistors are first connected in parallel and then in series. The resultant resistance in first combination to the second will be A 9 times B 1/9 times C 1/3 times D 3 times Answer : B Explanation :
19.
 Which method can be used for absolute measurement of resistances? A Lorentz method B Releigh method C Ohm’s law method D Wheatstone bridge method Answer : D Explanation :
20.
 Three 6 ohm resistors are connected to form a triangle. What is the resistance between any two corners? A 3/2 Ω B 6 Ω C 4 Ω D 8/3 Ω Answer : C Explanation :
21.
 Ohm’s law is not applicable to A Semi-conductors B DC circuit C Small resistors D High currents Answer : A Explanation :
22.
 Specific resistance of a substance is measured in A Ω/m B Ω/m2 C Ω-m D Ω/m Answer : C Explanation :
23.
 A nichrome wire used as a heater coil has the resistance of 2Ω/m. for a heater of 1 Kw at 200 V, the length of wire required will be A 80 m B 60 m C 40 m D 20 m Answer : A Explanation :
24.
 Temperature co-efficient of resistance is expressed in terms of A Ohms/0C B Mhos/ Ohms0C C Ohms /Ohms0C D Mhos/0C Answer : C Explanation :
25.
 Which of the following materials has the least resistivity? A Zinc B Lead C Mercury D Copper Answer : D Explanation :
26.
 Which of the following lamps will have least resistance at room temperature? A 25 W,  220 V B 100 W,  220 V C 200 W,  220 V D 60 W,  220 V Answer : C Explanation :
27.
 Which resistor will be physically larger in size? A 100Ω , 10 W B 10Ω , 50 W C 1MΩ , 1/2 W D 1KΩ , 1 W Answer : B Explanation :
28.
 When current flows through heater coil it glows but supply wiring does not glow because A Current through supply line flows at slower speed B Supply wiring is covered with insulation layer C Resistance of heater coil is more than the supply wires D Supply wires are made of superior material Answer : C Explanation :
29.
 The condition for the validity under ohm’s law is that A Resistance must be uniform B Current should be proportional to size of resistance C Resistance must be wire wound type D Temperature at positive end should be more than the temperature at negative end Answer : A Explanation :
30.
 Which of the following statement is correct? A A semi-conductor is a material whose conductivity is same as between that of a conductor and an insulator B A semi-conductor is a material which has conductivity having average value of conductivity of metal and insulator C A semi-conductor is one which conducts only half of the applied voltage D A semi-conductor is a material made of alternate layers of conducting material and insulator Answer : A Explanation :
31.
 A rheostat differs from potentiometer in the respect that it A Has lower wattage rating B Has higher wattage rating C Has large number of turns D Offers large number of tapings Answer : B Explanation :
32.
 The weight of an aluminum conductor of identical cross-section, for the same electrical resistance is A 50% B 60% C 100% D 150% Answer : A Explanation :
33.
 An open resistor, when checked with an ohm-meter reads A Zero B Infinite C High but within tolerance D Low but not zero Answer : B Explanation :
34.
 _______________   are the materials having electrical conductivity much less than most of the metals but much greater than that of typical insulators. A Varistors B Thermistor C Semi-conductor D Variable resistors Answer : C Explanation :
35.
 All good conductors have high A Conductance B Resistance C Reluctance D Thermal conductivity Answer : A Explanation :
36.
 Voltage dependent resistor are usually made from A Charcoal B Silicon carbide C Nichrome D Graphite Answer : C Explanation :
37.
 Voltage dependent resistors are used A For inductive circuits B To suppress surges C As heating elements D As current stabilizers Answer : B Explanation :
38.
 The ratio of mass of proton to that of the electron is nearly A 1840 B 1804 C 30 D 4 Answer : A Explanation :
39.
 The number of electrons in the outer most orbit of carbon atom is A 3 B 4 C 6 D 7 Answer : B Explanation :
40.
 With three resistances connected in parallel, if each dissipates  20 W  the total power supplied by the voltage source equals A 10 W B 20 W C 40 W D 60 W Answer : D Explanation :