Basic Electrician MCQS In English-1

1. Bulbs in street lighting are connected to all

(A) parallel

(B) series

(C) Series-parallel

(D) End-to-end

Answer: (A)

2. Test lamp must have wattage for testing appliances

(A) is very low

(B) less

(C) high

(D) any value

Answer: (C)

3. Switching a lamp in a house produces noise in the radio. This is because switching produces operation

(A) arcs to separate contacts

(B) High intensity mechanical noise

(C) arcs between both mechanical noise and contacts

(D) None of the above

Answer: (A)

4. When a load is switched off in a circuit, sparking occurs due to whose value is higher in the circuit.

(A) resistance

(B) induction

(C) Capacity

(D) impedance

Ans: (B)

5. A copper wire of fixed length and resistance is stretched and stretched three times its length without changing its volume, how much will the resistance of the wire change

(A) 1/9 times

(B) 3 times

(C) 9 times

(D) unchanged

Answer: (C)

6. When the resistance element of a heater fuses and then we reconnect it after removing a part of it, what will be the power expenditure of the heater

(A) deficiency

(B) growth

(C) remain constant

(D) None of the above

Ans: (B)

7. A field of force can only exist between

(A) two molecules

(B) two ions

(C) two atoms

(D) two metal particles

Ans: (B)

8. A substance whose molecules have dissimilar atoms.

(A) semi-conductor

(B) super conductor

(C) compound

(D) insulator

Answer: (C)

9. International ohm is defined in terms of resistance

(A) A column of mercury

(B) a cube of carbon

(C) A cube of copper

(D) unit length of wire

Answer: (A)

10. Three resistors are connected first in parallel and then in series. The resulting resistance of the first to second combination will be

(A) 9 times

(B) 1/9 times

(C) 1/3 time

(D) 3 times

Ans: (B)

 

11. When we install a 2000 watt heater in the wire of the house, then the heater turns red when the wiring wires stay cool because?

(A) Heater element has more current than wiring

(B) Element wire is naked so can feel its heat

(C) Element registration is less than warping

(D) Element registration is higher than wiring

Answer- (D)

12. When we install a 1500 watt heater in the wiring of the house, the light of the bulb decreases because?

(A) More current is taken by the heater and less current is left for the bulb to burn.

(B) A high voltage is dropped parallel to the heater and the bulb receives a low voltage

(C) There is a high voltage drop in the line and the lamp and heater get low voltage.

(D) Due to over-voltage drop in the line, the bulb receives low voltage but no effect on the heater

Answer - (C)

13. Which effect is produced when electric current flows in the circuit?

(A) thermal effect occurs

(B) is the optical effect

(C) chemical effect

(D) All of the above are effects

Answer- (D)

14. What supplies are needed for transistor radios?

(A) low voltage DC

(B) low voltage AC

(C) High voltage AC

(D) High voltage DC

Answer- (A)

15. If 20 resistances of 20 ohms are connected in parallel, then what will be its combined resistance?

(A) 1

(B) 2

(C) 10

(D) 100

Answer- (A)

16. Which lamp has higher resistance?

(A) 200 watts, 250 volts

(B) 100 watts, 250 volts

(C) 60 watts, 250 volts

(D) 40 watts, 250 volts

Answer- (D)

17. Three low rated lamps have been added to the 250 volt supply in the series. Which lamp will give more light?

(A) 200 watts, 250 volts

(B) 100 watts, 250 volts

(C) 60 watts, 250 volts

(D) 40 watts, 250 volts

Answer- (A)

18. If a 100 watt 230 volt lamp is connected to a 250 volt supply?

(A) will give more light than 230 volt supply

(B) will give less light than 230 volt supply

(C) will give light as much as 230 volt supply

(D) None of these

Answer- (A)

19. When a heater coil burns, remove the burnt part and start the heater again, then the power of the heater?

(A) will decrease

(B) will increase

(C) as much as before

(D) All three of the above

Answer- (B)

20. When the electric current flows through the carbon filament, the resistance of the filament is reduced because?

(A) due to temperature rise

(B) due to increasing positive temperature

(C) Negative temperature due to coefficient

(D) due to decrease in insulating properties

Answer - (C)

 

21. When current flows through the heater coil it glows but the supply wiring does not glow because

(A) Current flows slowly through the supply line

(B) Supply wires are covered with insulation layer

(C) The resistance of the heater wire is greater than the supply wires

(D) Supply wires are made of superior material

Answer: (C)

22. The condition for validity under Ohm's law is that

(A) resistance should be uniform

(B) should be proportional to the size of current resistance

(C) Resistance should be wire wound type

(D) Temperature at positive end should be higher than temperature at negative end

Answer: (A)

23. A rheostat differs from a potentiometer in that it

(A) wattage is low

(B) has high wattage rating

(C) There are a large number of rotations

(D) provides a large number of tapping

Ans: (B)

24. Aluminum conductors weigh more than copper conductors of the same cross-section for the same electrical resistance

(A) 50%

(B) 60%

(C) 100%

(D) 150%

Answer: (A)

25. An open resistor is tested with an ohm-meter. What will be the reading of the ohm-meter?

(A) zero

(B) infinite

(C) high but within tolerance

(D) low but not zero

Ans: (B)

26. They are materials that are much lower in electrical conductivity than most metals, but much higher than typical insulators.

(A) Varistors

(B) thermistor

(C) semiconductor

(D) variable resistor

Answer: (C)

 

27. All good conductors have high

(A) conduction

(B) resistance

(C) reluctance

(D) thermal conductivity

Answer: (A)

28. Voltage dependent resistors are usually made

(A) Charcoal

(B) silicon carbide

(C) nichrome

(D) graphite

Answer: (C)

29. Voltage dependent resistors are used

(A) for inductive circuits

(B) to suppress surges

(C) as heating elements

(D) as current stabilizers

Ans: (B)

30. The ratio of mass of electron to proton is approx.

(A) 1840

(B) 184

(C) 30

(D) 4

Answer: (A)

31. The number of electrons in the outer most orbit of a carbon atom is

(A) 3

(B) 4

(C) 6

(D) 7

Ans: (B)

32. With three resistors connected in parallel, the total power supplied by the voltage source becomes equal if each consumes 20 W.

(A) 10 W

(B) 20 W

(C) 40 W

(D) 60 W

Answer: (D)

33. A thermistor is

(A) positive temperature coefficient

(B) negative temperature coefficient

(C) zero temperature coefficient

(D) variable temperature coefficient

Answer: (C)

34. If I, R and t are current, resistance and time respectively, then the ratio of heat produced according to Joule's law will be

(A) I²Rt

(B) I²Rf

(C) I²R²t

(D) I²R²t *

Answer: (A)

35. Nichrome wire is of an alloy

(A) lead and zinc

(B) Chromium and Vanadium

(C) Nickel and Chromium

(D) copper and silver

Answer: (C)

36. When a voltage of one volt is applied, a circuit allows a micro ampere current to flow. The conductance of the circuit is

(A) 1 n-mho

(B) 10⁶ mho

(C) 1 milli-mho

(D) None of the above

Answer: (A)

37. Which of the following can have a negative temperature coefficient?

(A) Silver compounds

(B) liquid metals

(C) Metallic alloys Metallic alloys

(D) electrolytes

Answer: (D)

38. conduction: mho ::

(A) resistance: ohm

(B) capacitance: henry

(C) inductance: farad

(D) lumen: steradian

Answer: (A)

39. 1 angstrom is equal to

(A) 10^-8 mm

(B) 10^-6 cm

(C) 10^-10 m

(D) 10^~14 m

Answer: (C)

40. A Newton meter is similar to

(A) one watt

(B) a joule

(C) five joules

(D) one joule second

Ans: (B)

41. Which of the following metals has the lowest resistivity?

(A) Copper

(B) Iron

(C) Iron

(D) Silver

Answer- (D)

42. The ability to conduct current of a copper wire whose diameter is twice that of other copper wire?

(A) will be double

(B) will be half

(C) will be four times

(D) will be three times

Answer - (C)

43. According to the second law of Kirchoffs?

(A) The mathematical sum of EMF is zero.

(B) the mathematical sum of the voltage drop is zero

(C) Mathematical sum of voltage drops and EMF's mathematical sum is zero

(D) Mathematical sum of voltage drops The mathematical sum of EMF is zero.

Answer- (D)

44. The resistance of each widening of a rotor connected in a delta is 3 ohms. Find the value of resistance between two pairs of terminals?

(A) 2 ohms

(B) 1.33 ohms

(C) 4 ohms

(D) 2 ohms

Answer- (D)

45. The voltage rating of 200 watt and 100 watt bulbs is the same, what will be the resistance of 100 watt bulbs?

(A) will be the same

(B) will be more

(C) will be less

(D) less first then later

Answer- (B)

46. D.C. In the case of

(A) The magnitude and direction of the stream remain constant

(B) The magnitude and direction of current changes over time

(C) the magnitude of the current changes over time

(D) the magnitude of the current remains constant

Answer :-( A)

47. When electric current passes through a bucket filled with water, a large amount of bubbling is seen. This shows what is the type of supply

(A) A.C.

(B) D.C.

(C) Either of the above

(D) None of the above

Ans: (B)

48. Resistance of carbon filament lamps when supply voltage increases.

(A) increases

(B) decreases

(C) remains same

(D) None of the above

Ans: (B)

49. Which of the following quantities remain the same in all parts of a series circuit?

(A) voltage

(B) present

(C) power

(D) resistance

Ans: (B)

50. A 40w bulb is connected in series with a room heater. If the 40w bulb is replaced with a 100w bulb now, the heater output will be

(A) lack

(B) growth

(C) stay the same

(D) the heater will burn

Ans: (B)