Quizizz Quiz - Electrical Engineering Quiz PDF

## Summary Remarkable win, keep it up! ## Khaled - 1660 coins ## Accuracy - 47150 ## Score - 2940 ## Performance Stats - Correct: 89 - Incorrect: 58 - Partially Correct: 0 - Time/ques: 2 m ## Review Questions 1. The distance that an Alternating Current (A.C.) travels in time period "T" is calle...

## Summary Remarkable win, keep it up! ## Khaled - 1660 coins ## Accuracy - 47150 ## Score - 2940 ## Performance Stats - Correct: 89 - Incorrect: 58 - Partially Correct: 0 - Time/ques: 2 m ## Review Questions 1. The distance that an Alternating Current (A.C.) travels in time period "T" is called **Frequency**. 2. A transformer has 100 turns in the primary coil and 25 turns in the secondary coil. When a 120 V is applied to the primary coil, the voltage in the secondary coil is **30V**. 3. Which of the following supply is given to the rotor winding of 3-Phase Induction Motor: **AC**. 4. In a series LRC circuit, if the capacitive reactance is equal to the inductive reactance, what is the phase angle between current and voltage? **0**. 5. The magnetic material for the core needs to be made of soft iron where its permeability is high **to reduce eddy current loss**. 6. The other name for the Shaded-Pole Motor is **Split Pole Motor**. 7. Thin laminated sheets of Iron are used instead of solid block to: **Reduce the eddy current effect**. 8. Which filters are commonly used because of their compact design and lower price: **CR-Filters**. 9. Electrical symbol of a TRANSFORMER: (The image shows a circuit diagram representing a transformer). 10. What is impedance? **the vector sum of resistance and total reactance**. 11. What happens at resonance? **Current is maximum**. 12. Which of the following does not change in a transformer? **Power**. 13. Synchronous Machine having 4 poles and supplied with 60 Hz supply will rotate at: **1800**. 14. In an RLC circuit, power loss can take place in **R and C**. 15. Regarding the relationship between frequency (f) and effective resistance (R): **R is independent upto 1000 Hz**. 16. Calculate voltage in the secondary coil based on the information given below. Vp 240 VNp = 20Ns = 125Vs? **1500 V**. 17. Which filters are used in smoothing circuits to cancel out the unintended AC parts in a rectifier: **Low Pass Filters**. 18. At resonace condition in a RLC serires circuit, the impedance will be **Minimum**. 19. What is the phase angle between the voltages of the inductor and capacitor in a RLC series circuit? **180°**. 20. What is the Peak voltage of the signal shown on the multimeter? **707 V**. 21. Assume primary has 240 turns and secondary has 60 turns. Primary is connected with 120V AC power supply. What is the voltage on the secondary? **30 V**. 22. According to Faraday's Law of Induction, the induced voltage in a coil is proportional to? **The rate of change of magnetic flux**. 23. 2 V 24. 120V 25. why is a centrifugal switch used in a 1-ph induction motor **To improve the starting performance of the motor**. 26. The Turns Ratio in a Transformer is calculated by the formula: **N1/N2**. 27. Which of the following statements about a series RCL circuit is true? **At resonance, the total reactance and total resistance are equal.** 28. In a shaded pole motor, shading coils are using to **produce rotating magnetic field**. 29. In large synchronous machine, field winding is placed on **Rotor, Stator**. 30. The repetition of a variable quantity, recurring at equal intervals, is known as **Period**. 31. The sum of resistance and reactance is referred to as **Impedance**. 32. What is the unit for capacitative reactance? **Ohm Farad**. 33. An inductor consisting of ohmic resistance and inductive reactance is applied to 115 V AC. Its current is 1 A. What is the impedence? **115 Ohms**. 34. The filters which let all frequencies pass, apart from a particular frequency band (channel) is called: **Band-Stop Filters**. 35. When a particular inductor is connected to a source of sinusoidal varying voltage with constant amplitude and a frequency of 60.0 Hz, the rms current is 3.0 A. What is the rms current if the source frequency is doubled? **3.0 A**. 36. A resistor is connected to an AC power supply. On this circuit, the current **is in phase with the voltage**. 37. In the given figure, which coil will have maximum induced voltage **S2**. 38. The value of a given waveform at any instant time is termed as **Instantaneous value**. 39. Which one of the below AC parameters shows the effective DC value? **RMS value**. 40. The total resistance of a circuit with resistance, capacitive reactance and inductive reactance is referred to as: **Impedance**. 41. A low pass filter is **Allows the higher frequencies**. 42. The magnetic field produced by an alternating current can be thought of as a **magnetic field**. 43. Which of the graphs below shows the characteristics for the circuit shown? The image shows a circuit diagram representing a capacitor and a resistor, with the output graph of Vout (voltage) over i (current) over time. The graph is a sinusoidal waveform and the closest match to the graph shown is **the first graph on the left, which shows the sinusoidal waveform.** 44. What kind of filter is shown in the figure? The image shows a circuit diagram with a Resistor and a capacitor. The filter shown in the figure is a **Low Pass Filter**. 45. This phasor diagram for: The image shows a phasor diagram with a phasor called "x". The diagram is for **R**. 46. Calculate potential difference in the secondary coil based on the information given below. Vp 240 VNp = 20Ns = 125Vs? **1000**. 47. The maximum instantaneous value measured from zero value is known as? **Peak to peak value**. 48. If the primary power of an ideal transformer having a 2:1 voltage ratio is 100 W, the secondary power is: **100 W**. 49. A resistor is connected to an AC power supply. On this circuit, the current **is in phase with the voltage**. 50. This phasor diagram for: The image shows a phasor diagram with a phasor called "x" and its components "R" and "L". The diagram is for **L**. 51. A coil with an inductance of 10 H is applied to an AC voltage of U = 230, f=50 Hz. Calculate the inductive reactance. (Pie value = 3.14) **314 ohms**. 52. This phasor diagram for: The image shows a phasor diagram with a phasor called "x" and its components "R" and "C". The diagram is for **C**. 53. The magnetic material for the core needs to be made of soft iron where its permeability is high **to reduce hysteresis loss**. 54. A capacitor with a capacitive reactance of 800 ohms is applied to an AC voltage U = 400 V. What is the current? **0.5 Amperes**. 55. Which of the following statements about capacitive reactance is true? **It is very small at low frequencies** 56. A pure inductor is connected to an AC power supply. In this circuit, the current **lags the voltage by 90°**. 57. The Parallel Resonant Circuit blocks certain frequency and therefore is known as: **Rejector Circuit**. 58. Find out the low pass filter from the given frequency response characteristics. The image shows 4 graphs. The graph showing a lowpass filter is **the first graph on the left, which shows that low frequencies pass through the system while high frequencies are attenuated.** 59. Laminated insulation is normally used in the transformer: **To reduce the hysteresis effect**. 60. The following impedance circuit shows the characteristics of a **Series resonance circuit**. 61. When can we use the 3-phase star connection without the neutral line? **When all the three loads are symmetrical**. 62. The unit of Impedence is: **Ohms**. 63. Transformer works on which of the following principle **Faraday's Law of Electromagnetic Induction**. 64. What happens when Induction motor runs at synchronous speed, motor will: **Stops**. 65. The unit for measuring Inductance (L) is **Henry**. 66. LAMINATED CORE IN A TRANSFORMER IS TO **REDUCE THE LOSS- EDDY CURRENT LOSS**. 67. The unit of frequency is **Hertz**. 68. In order for electromagnetic induction to occur, there must be relative.......between a magnetic field and a conductor. **Motion**. 69. Transformer is always connected to **AC** supply. 70. If the resistance in an AC series circuit remains the same, but the capacitance and inductance are each doubled, how will the resonance frequency change? **Reduced by a factor of 2**. 71. Electric currents passing through wires will produce a(n) **magnetic field**. 72. The function of a transformer is to... **raise and lower the apparent power levels**. 73. If an Alternating Current (A.C) takes 10 seconds to complete 1 Cycle. Calculate the frequency: **0.1 Hertz**. 74. If the peak to peak value of an Alternating Current is 4 Amperes (A). The Root Mean Square (RMS) Value would be: **2.828 A**. 75. The Diodes connected parallel to the inductor coil to prevent the extremely high current when switched off, is called: **Free Wheeling Diodes**. 76. Which of the following statements can be true for a resistor connected in a simple series circuit to an operating AC generator? I. The average power dissipated in the resistor is positive. II. The average power dissipated in the resistor is zero. III. The average current is zero. **I only**. 77. The following impedance circuit shows the characteristics of a **Series resonance circuit**. 78. Which of the following supply is given to the rotor winding of 3-Phase Induction Motor: **AC**. 79. What are the symbols for impedance, reactance and resistance? **Z, X, R**. 80. The variation of voltage across an AA inductor with time t in an a.c. circuit is as shown in the graph. Which graphs shows the variation of the current I which flows through the inductor with time t? The image shows a graph of the voltage across the inductor represented by a sinusoidal waveform. The closest match to this graph is **the first graph on the left, which shows the current following the sinusoidal waveform, but with a phase shift. The phase shift is because the current lags the voltage by 90 degrees in an inductor.** 81. Which factor is not considered for synchronization? **Voltage**. 82. An LRC resonates when the applied frequency is equal to **1/2*π√(LC)** 83. Efficiency of a transformer is **(output power)/(input power) x100%**. 84. The most common waveforms of ac is **sine wave**. 85. The inductance of a coil increases with: **Increasing number of turns**. 86. The power factor in an AC circuit is defined as: **The ratio of real power to apparent power**. 87. The formula for inductive reactance is **XL = 2πfL**. 88. In order for electromagnetic induction to occur, there must be relative between a magnetic field and a conductor. **Motion**. 89. If the frequency of the AC voltage across an Inductor is doubled, the inductive reactance of that inductor **Increases to twice its original value.** 90. The phenomenon of inducing a voltage in a conductor by changing the magnetic field around it is called: **Electromagnetic induction**. 91. The distance that the electrical current travels in the cycle time (T) is called: **Wavelength**. 92. Which of the graphs below shows the characteristics for the circuit shown? The image shows a circuit diagram representing a capacitor and a resistor, with the output graph of Vout (voltage) over i (current) over time. The graph is a sinusoidal waveform and the closest matchto the graph shown is **the second graph from the left, which shows that the current lags behind the voltage by 90°.** 93. This picture is an example of a **Step-up transformer**. 94. A transformer does not change the following: **Frequency**. 95. Why transformers work with A.C. current but not D.C. **A.C current produces changing magnetic field..** 96. In Aeroplanes, which types of A.C. (Alternating Current) Motors are often found? **Three Phase Asynchronous Motors**. 97. Ratio of voltages is equal to ratio of **number of turns in coil**. 98. What is the test conducted on a transformer to know the copper loses **Short circuit test**. 99. The function of a generator is to change **mechanical energy to electrical energy.** 100. An inductor of inductance 22.0 mH is connected to an a.c. supply with frequency f. If the reactance of the Inductor is 660 Ω, what is the value of f? **3.00undefined Hz**. 101. The current in an inductor connected to an AC voltage source lags the voltage. The lag is caused by the **back emf in the coil**. 102. The special frequency where the Inductive Reactance and Capacitive Reactance cancel out each other is called: **Resonance Frequency** 103. Which of the following is/are true regarding a series RLC circuit? a. A capacitor will be dominant at higher frequencies. b. an inductor will be dominant at higher frequencies. c. Maximum current flows through the circuit at the resonant frequency. **a and c**. 104. The filters which let voltages with high frequencies (above cut off frequency) easily pass is known as: **High-Pass Filters**. 105. The function of a transformer is to..... **raise and lower the apparent power levels**. 106. The Power of Alternating Current (A.C.) Generators and Transformers is given in: **Volt Ampere (VA)**. 107. Transformer works on which of the following principle **Faraday's Law of Electromagenetic Induction**. 108. Write an equation that solves for the Impedance, Ztotal, of this series circuit. **Ztotal = √(R2+X2)** 109. In RLC circuit, If R is the resistance, XL is the inductive reactance and XC is the capacitive reactance, the impedance Z of the circuit is: **√(R2+(−XL+XC)2)** 110. Why transformers work with A.C. current but not D.C. **A.C current produces changing magnetic field..** 111. For a transformer copper losses are also known as **eddy current loss**. 112. If an electric bulb is connected to an AC source, which of the following statement is true about the phase difference between the voltage across the bulb and current flowing in it? **Not in phase.** 113. The voltage is leading the current. 114. If the inductive reactance is smaller than the capacitive reactance, then the current **leads the supply voltage.** 115. Electromagnetic Induction is.. **The process of inducing an emf (voltage) with a change in magnetic flux** 116. On aircraft, the Alternating Current (A.C.) Voltages found are: **115 Volts and 200 Volts**. 117. Moving a permanent magnet through a coil of wire will **a current will be generated in the wire**. 118. A transformer has primary voltage 200V and secondary voltage 100V, the transformer is called **Step Down**. 119. A pure capacitor is connected to an AC power supply. In this circuit, the current **leads the voltage by 90°**. 120. This picture is an example of a **Step-Down Transformer**. 121. A transformer has 100 turns in the primary coil and 25 turns in the secondary coil. When a 120 V is applied to the primary coil, what is the voltage in the secondary coil? **30V**. 122. In the given figure, If the current the first coil increased, what will happen to the induced voltage in the second coil **Increase**. 123. Ratio of voltages is equal to ratio of **number of turns in coil**. 124. In a circuit with inductive reactance, the current lags the applied voltage by: **90 Degrees**. 125. A capacitor 120 µF is connected to an AC source of 6 V with frequency 100 Hz. If the frequency is increased to 200 Hz, the reactance of the capacitor will be **half the original value**. 126. coil is also known as: The self-induced voltage in a coil is also known as: **Back EMF**. 127. A single Phase Induction motor is self starting **True**. 128. In a series circuit current must be **constant for each element**. 129. A pure inductor is connected to an AC power supply. In this circuit, the current **lags the voltage by 90°**. 130. The sum of Hysteresis and Eddy current losses are also called **Heat loss**. 131. The average value of Alternating current of a full sinusoidal cycle is **Zero**. 132. A **Low pass** filter significantly attenuates all frequencies below fc and passes all frequencies above fc. 133. What is alternating current **Electric currents whose direction and magnitude change periodically depending on time**. 134. The current caused by an induced voltage always opposes the cause of the induction. This law is called: **Lenz's Law**. 135. If the frequency of the AC voltage across an Inductor is doubled, the inductive reactance of that Inductor **Increases to twice its original value.** 136. The opposition to AC current flow presented by capacitors and inductors is called: **Reactance**. 137. Alternating voltage (V) is represented by the equation **V(t)=Vm sin wt** 138. The capacitor in a capacitor-start induction run ac motor is connected in series with **starting winding**. 139. Which one of the below AC parameters show the effective Dc value? **RMS value**. 140. An RLC circuit has a resonance frequency of 60 HZ.. When this circuit is operated at 30 HZ, the voltage **lags** the current because **XC is more than XL**. 141. A Capacitor blocks **Only a.c**.