Module 3 Module 3 quiz contains 52 question based on the syllabus for module 3 examination for B1.1, B1.3 and B2 category. The time limit for the quiz is 65 min. The number of attempts allowed are unlimited. All the best. Name 1. What is the effective value of current? RMS current Instantaneous current Average current None 2. The most common form of primary cell is: the zinc carbon where carbon is positive zinc is negative and the output is 1.5V made from nickel cadmium with a potential of 2V between the plates a lead acid cell with the terminals of lead peroxide and spongy lead giving 2.1V None 3. An electromagnet of resistance 16ohm requires a current of 1.5A, the voltage required is: 24V 18V 11V None 4. Coercive force is the: max magnetic strength of a material even if magnetising force increased magnetising force required to cancel magnetic strength of a material max magnetic strength of a material once magnetising force removed from coil None 5. The unit in which chemical energy produces opposite charges on 2 dissimilar metals is: a capacitor a battery cell a photocell None 6. High torque low speed is given by: series DC motor compound DC motor shunt DC motor None 7. An inductor of 50mH is connected in series with a resistance of 10kΩ. The time taken for the current to reach 63.2% of the maximum is: 5 μS 50 μS 500 μS None 8. A component is required to have a positive temperature coefficient value. It is likely to be made of: Silicon Copper Carbon None 9. When comparing 2 alternating current waveforms, one is at its maximum value while the other is at zero. The two waveforms are: 45° out of Phase 90° out of Phase of opposite phase angle None 10. Hysteresis losses are much: lower in magnetically hard materials like steel higher with higher applied frequencies higher in magnetically soft material like iron None 11. Three resistors of equal value connected in parallel in a circuit. If one of the resistors becomes an open circuit, the current through the circuit will: Stay the same Decrease Increase None 12. What is the resistance and tolerance value of a resistor colour coded, yellow, Violet and brown: 470 ohm +/-20% 47ohm +/-20% 4.7 ohm +/-10% None 13. In an electrical circuit, EMF (electro motive force) and PD (potential difference): are the same with no load applied can only be the same with correct load matching will only be the same if internal resistance is negligible None 14. Find the current in the circuit 3 A 1 A 2 A None 15. The two factors which govern the output frequency of an AC generator are the: speed of rotation of the rotor and the stator field flux strength the number of poles (in pairs) and the rotor RPM strength of the stator field flux and number of poles None 16. If a length of wire is cut in half and the two halves connected in parallel the resistance is” The same as the original Half the original Quarter of the original None 17. In the diagram an unknown resistance is being measured using a Wheatstone bridge. The bridge is balanced. The unknown resistance is: 60 Ω 150 Ω 10 Ω None 18. If the current through x ohm resistance in the circuit is 5A, find the value of x 135 ohm 27 ohm 12 ohm 5 ohm None 19. A sine wave has a periodic time of 0.5 milliseconds. What is the frequency? 20kHz 2kHz 200Hz None 20. Friction can induce electrostatic charge of very: high voltage on conducting surfaces ow voltage on insulated surfaces high voltage on insulated surfaces None 21. The charge of 25 x 10^18 electrons is Approximately: 3 coulombs 2 coulombs 4 coulombs None 22. The aircraft power supply frequency is 400 hertz. The period is: 0.0025 seconds 0.004 seconds 0.006 seconds None 23. The value of a given waveform at any instant time is termed as Period Waveform Instantaneous value Cycle None 24. A charge of 36 coulombs moves passed a point in 3 seconds. The flow in amps is: 108 33 12 None 25. Four 10F capacitors are connected in series, calculate the equivalent capacitance. 1.5F 2.5F 40F None 26. Strength of the electric field is Directly proportional to the square of the force applied Directly proportional to the force applied Inversely proportional to the square of the force applied Inversely proportional to the force applied None 27. Through which material will magnetic lines of force pass the most readily? Iron Copper Aluminium None 28. If an EMF (Electro Motive Force) of 120v is applied to a circuit of three equal value resistors in series and a current of 2A flows the value of each resistor is: 20 ohm 60 ohm 80 ohm None 29. In an induction motor: the armature and field coils are connected in series a rotor with no connections follows a rotating magnetic field a DC –energised rotor follows a rotating magnetic field None 30. When capacitors are connected in parallel, what happens to the effective plate area? Decreases Increases Remains the same Becomes zero None 31. Two 10V 20AH batteries are connected in parallel and connected across a 10Ω load. How long could they supply the required load current before the voltage began to decay? 40 hours 4 hours 10 hours None 32. Which of the following is a passive device? Capacitor Rectifier Transistor None 33. In a parallel circuit, with a number of resistors, the voltage across each resistor is Is divided proportionally across all resistors Is divided equally among all resistors The same for all resistors None 34. A transformer has 100V applied to the primary. If the ratio is 1:3 and the secondary current is 6A, the primary current will be: 6A 2A 18A None 35. A 24V source is connected across a 30 Kohm resistor. In order to achieve a current flow of 6mA the resistor must be changed to 4 Kohm 7.5 Kohm 144 mohm None 36. Time constant of an inductor is: L/R R/L LR None 37. The voltage waveform in an ideal inductance would be: 90° lagging the current 90° leading the current In phase with the current None 38. Where the resistance of the load equals the internal resistance of the battery: circuit losses are at a maximum power in the load is at a maximum voltage across the load is at maximum None 39. In an RLC circuit, the power factor is always Depends on the circuit Positive Negative Zero None 40. Calculate the time constant of a series RC circuit consisting of a 100microF capacitor in series with a 100ohm resistor. 0.1 msec 0.01 sec 0.1 sec 0.01 msec None 41. An alternating electromotive force is applied to a pure resistance. Current and voltage : are in phase are in anti-phase phase angle dependent on frequency None 42. The torque speed characteristic of a series motor is: high torque, low speed low torque, low speed high torque, high speed None 43. Air has a dielectric constant of Infinity Zero Unity None 44. Calculate the charge in the 2F capacitor 200C 100C 50C None 45. If 4 equal resistance conductors are connected in parallel their total resistance is: a quarter the of one wire half the resistance of one wire an eighth of one wire None 46. If four Identical cells of 2.2 volt and 15 amp/hour (A/H) capacity are connected in series the voltage and A/H will be: 8.8V 60A/H 8.8V 15A/H 2.2V 15A/H None 47. An alternating current circuit contains resistance and no reactance the phase angle between voltage and current will be: 45 90 zero None 48. Wave and Lap windings are designed to give: high ripple and low ripple respectively high voltage and high current respectively high current and high voltage respectively None 49. The peak-to-peak value of a sine wave of 150V is: 300 V 424.4V 212.2V None 50. A material with a high value of resistivity: will not allow a current to flow through it will be a good conductor if kept cold would not be suitable as a conductor None 51. A conductor with a positive Q (charge) of 4C has 12.56 x 10^18 electrons added it will have a Q =: 4 2 0 None 52. What is the power factor of a series RLC circuit under resonance condition? 1 0 Infinity None 1 out of 1
