electrical basic ques

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1) Resistivity of a wire depends on

A.materialB.lengthC.cross-section-areaD. all of above

2) When n numbers resistances of each value r are connected in parallel, then the resultant resistance is x. When these n resistances are connected in series, total resistance is

A.nx.B.n2x.C.x/n. D. rnx.

3) Resistance of a wire is r ohms. The wire is stretched to double its length, then its resistance will be

A.r/2 B.4r C.2r D. r/4

4) Kirchhoff’s second law is based on law of conservation of

A.chargeB.energyC.momentumD. mass



5) One coulomb of electrical charge is contributed by how many electrons ?

A.0.625X1019.B.1.6X1019.C.1019.D. 1.6 X 1012.

6) Tow bulbs marked 200 watts – 250 V, and 100 watts – 250 V are joined in series to 250 V supply. The power consumed by the circuit is

A.33watt B.200wattC.300wattD. 67 watt.

7) Ampere second is the unit of

A.conductanceB.powerC.energyD. charge

8) Which of the following is not the unit of electrical power

A.volt/ampereB.voltampere C.wattD. joule/second



9) One kilowatt hour is same as

A.36X105 wattB.36X105 ergsC.36X105 joules D. 36 X 105 BTU

10) An electric current of 6 A is same as

A.6joule/secondB.6Coulomb/second.C.6watt/secondD. none of the above.

11) A circuit contains two un equal resistor in parallel

A. voltage drops across both are sameB. currents in both are sameC. heat losses in both are sameD. voltage drops are according to their resistive value

12) Conductance of any conductor is expressed as

A. ampere/wattB. mhoC. volt2/wattD. watt/ampere2

13) A copper wire of length l and diameter d has potential difference V applied at its two ends. The drift velocity is vd. If the diameter of the wire is made d/2, then the drift velocity becomes

A. vd.B. 4vd.



C. vd/4.D. vd/2.

14) Two resistances R1 and R2 give combined resistances 4.5Ω and 1Ω when they are connected in series and parallel respectively. What would be the values of these resistances ?

A. 3Ω and 6Ω B. 1.5Ω and 3ΩC. 3Ω and 9ΩD. 6Ω and 9Ω

15) Which of the following may be value of resistivity of copper

A. 1.7 X 10 – 6

B. 1.7 X 10 – 5

C. 1.7 X 10 – 4

D. 1.7 X 10 – 3.

16) Mass of a proton is how many times greater than mass of an electron

A. 184000B. 18400C. 1840D. 184

17) Two equal resistors R connected in series across a voltage source V dissipate power P. What would be the power dissipated in the same resistors when they are connected in parallel across the same voltage source ?

A. 4PB. PC. 2PD. 16P

18) Two identical resistors are first connected in parallel then in series. The ratio of resultant resistance of the first combination to the second will be

A. 4B. 0.25



C. 2 D. 0.5

19) The ratio of the resistance of a 200W, 230V lamp to that of a 100W, 115V lamp will be

A. 0.5 B. 2 C. 4 D. 0.25

20) The resistance of 200W 200V lamp is

A. 100 ΩB. 200 ΩC. 400 ΩD. 800 Ω

21) Tow 1 kΩ 1 W resistors are connected in series. Their combine resistance and wattage will be

A. 2 kΩ, 0.5 WB. 1 kΩ, 1 WC. 0.5 kΩ, 2 WD. 2 kΩ, 1 W

22) Three 3 Ω resistors are connected to form a triangle. What is the resistance between any two of the corners ?

A. 9 ΩB. 6 ΩC. 3 ΩD. 2 Ω.

23) A wire of 0.14 mm diameter and specific resistance 9.6 μΩ – cm is 440 cm long. The resistance of the wire will be

A. 9.6 ΩB. 11.3 ΩC. 13.7 ΩD. 27.4 Ω

24) A 10 Ω resistor is stretched to increase its length double. Its resistance will now be



A. 40 ΩB. 20 Ω

C. 10 ΩD. 5 Ω

25) Specific resistance is measured in

A. mhoB. ohm C. ohm – cm D. ohm/cm

26) A wire of resistance R has it length and cross – section both doubled. Its resistance will become

A. 0.5RB. R.C. 2RD. 4R

27) 5 X 1016 electrons pass across the section of a conductor in 1 minutes and 20 seconds. The current flowing is

A. 0.1 mA. B. 1 mAC. 10 mAD. 100 mA

28) Three element having conductance G1, G2 and G3 are connected in parallel. their combined conductance will be

A. (G1 + G2 + G3) – 1

B. G1 + G2 + G3

C. 1/G1 + 1/G2 + 1/G3

D. (1/G1 + 1/G2 + 1/G3) – 1

29) Which of the following has negative temperature coefficient ?

A. Electrolytes.B. Brass.



C. Copper.D. Silver.

30) Which of the following has positive temperature coefficient ?

A. Germanium. B. GoldC. PaperD. Rubber

31) Four resistance R1, R2, R3, & R4 are connected in series across a 220V supply. The resistances are such that, R1 > R2 > R3 > R4. The least power consumption will be in

A. R2

B. R4

C. R1

D. R3

32) 200 resistors of 200 Ω each are connected in parallel. Their equivalent resistance will be

A. 1 ΩB. 200 Omega;C. 400 Omega; D. 4 kΩ

33) The resistance of 100W, 200V lamp is

A. 200 Ω B. 400 ΩC. 800 ΩD. 1600 Ω

34) A 1 kΩ, 1W resistor can safely pass a current of

A. 30 mAB. 60 mAC. 40 mAD. 100 mA



35) When ac flows through a pure inductance then the current

A. is in phase with emfB. lags the emf by – 90o

C. lags the emf by 90o D. leads the emf by 90o

36) When ac flows through a pure capacitance then the current

A. leads the emf by 90o

B. lags the emf by 90o

C. leads the emf by – 90o D. is in phase with emf

37) Which of the following materials has highest electrical conductivity ?

A. SteelB. AluminiumC. CopperD. Silver

38) Which of the following has least conductivity?

A. SilverB. CopperC. AluminumD. Gold

39) It three capacitors of capacitance value 1μF 2μF & 3μF are connected in parallel than what will be the equivalent capacitance of that combination.

A. 6 μFB. 1.83 μFC. 0.546 μFD. 3 μF

40) It three capacitance of values 1μF,2μF & 3μF are connected in series then, what will be equivalent capacitance of the combination.

A. 6 μFB. 0.546 μFC. 1.83 μFD. 3 μF

electrical basic ques

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