Multiple Choice Questions [MCQ] on Basic Electrical Engineering -Part16

Multiple Choice Questions [MCQ] on Basic Electrical Engineering -Part16

Objective Type Questions on Basic Electrical Engineering -Part16

[1]  A 240V, 60W lamp has a working resistance of:
(a) 1400Ω
(b) 60Ω
(c) 960Ω
(d) 325Ω

Ans: C

[2] The symbol for the unit of temperature coefficient of resistance is:
(a) Ω /°C
(b)Ω
(c) °C
(d) Ω /Ω°C

Ans: D

[3] The length of a certain conductor of resistance 100Ω is doubled and its cross-sectional area is halved. Its new resistance is:
(a) 100Ω
(b) 200Ω
(c) 50Ω
(d) 400Ω

Ans: D

[4] Voltage drop is the:
(a) Maximum potential
(b) Difference in potential between two points
(c) Voltage produced by a source
(d) Voltage at the end of a circuit

Ans: B

[5] The largest number of 100W electric light bulbs which can be operated from a 240V supply fitted with a 13A fuse is:
(a) 2
(b) 7
(c) 31
(d) 18


[6] When an atom loses an electron, the atom:
(a) Becomes positively charged
(b) Disintegrates
(c) Experiences no effect at all
(d) Becomes negatively charged

Ans: A

[7] The energy used by a 1.5kW heater in 5 minutes is:
(a) 5 J
(b) 450 J
(c) 7500 J
(d) 450 000 J

Ans: D

[8] The unit of resistivity is:
(a) ohms
(b) ohm millimetre
(c) ohm metre
(d) ohm/metre

Ans: C

[9] A resistor marked as4K7G indicates a value of:
(a) 47Ω ±20%
(b) 4.7Ω k ±20%
(c) 0.47Ω ±10%
(d) 4.7 kΩ ±2

Ans: D

[10] The resistance of a 2 km length of cable of cross-sectional area 2mm² and resistivity of 2×10^-8Ω m is:
(a) 0.02Ω
(b) 20Ω
(c) 0.02mΩ
(d) 200Ω

Ans: B

[11] A piece of graphite has a cross-sectional area of 10mm². If its resistance is 0.1Ω and its resistivity 10×10⁸ Ωm, its length is:
(a) 10 km
(b) 10 cm
(c) 10 mm
(d) 10 m

Ans: D

[12] A nickel coil has a resistance of 13Ω at 50°C. If the temperature coefficient of resistance at 0°C is 0.006/ °C, the resistance at 0°C is:
(a) 16.9Ω
(b) 10Ω
(c) 43.3Ω
(d) 0.1Ω

Ans: B

[13] A coil of wire has a resistance of 10 at 0°C. If the temperature coefficient of resistance for the wire is 0.004/ °C, its resistance at 100°C is:
(a) 0.4Ω
(b) 1.4Ω
(c) 14Ω
(d) 10Ω

Ans: C

[14] A colour coding of red-violet-black on a resistor indicates a value of:
(a) 27Ω ±20%
(b) 270Ω
(c) 270Ω ±20%
(d) 27Ω ±10%

Ans: C

[15] An inductance of 10mH connected across a 100V, 50 Hz supply has an inductive reactance of
(a) 10π
(b) 1000π
(c) π
(d) π H

Ans:C

What is the difference between earthing, grounding and neutral

Earthing and Grounding are two different simple concepts which people often gets confused. Let me explain both of these things in simpler manner. *.Earthing means connecting the dead part (it means the part which does not carries current under normal condition) to the earth. For example electrical equipment’s frames, enclosures, supports etc. Whilegroundingmeans connecting the live part (it means the part which carries current under normal condition) to the earth. For example neutral of power transformer. *.The purpose ofearthingis to minimize risk of receiving an electric shock if touching metal parts when a fault is present. While the purpose ofgroundingis the protections of power system equipment and to provide an effective return path from the machine to the power source. For example grounding of neutral point of a star connected transformer. *.Groundis a source for unwanted currents and also as a return path for main current some times. Whileearthingis done not for return path but only for protection of delicate equipments.

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