Electrical Engineering Quiz

Summary

• Remarkable win, keep it up!
• 1660 coins
• 47,150 Score
• 2,940 Coins
• 60% Accuracy
• 89 Correct answers
• 58 Incorrect answers
• 2 Partially correct answers

Review Questions

• Question 1: The distance an alternating current (AC) travels in time period "T" is called wavelength.
• Question 2: A transformer has 100 turns in the primary coil and 25 turns in the secondary coil. When 120V is applied to the primary coil, the voltage in the secondary coil is 30V.
• Question 4: The supply given to the rotor winding of a 3-phase induction motor is AC.
• Question 5: In a series LRC circuit, if capacitive reactance equals inductive reactance, the phase angle between current and voltage is 90°.

Other Questions

• Question 6: Magnetic material for the core needs to be soft iron for high permeability to reduce eddy current loss and hysteresis loss.
• Question 7: Another name for a shaded-pole motor is a split-pole motor.
• Question 8: Thin laminated sheets of iron are used instead of a solid block to reduce eddy current effect.
• Question 12: Electrical symbol of a transformer is shown.
• Question 15: Impedance is the vector sum of resistance and total reactance.
• Question 16: At resonance, impedance is maximum.
• Question 17: Current does not change in a transformer.
• Question 18: A synchronous machine with 4 poles and a 60 Hz supply rotates at 1500 rpm.
• Question 19: In an RLC circuit, power loss can occur in Resistance (R), Inductor (L), and Capacitor (C).
• Question 21: Regarding the relationship between frequency (f) and effective resistance (R), R is directly proportional.
• Question 23: Calculating transformer voltage: Vp = 240v, Np = 20, Ns = 125, Vs. =1500V.
• Question 24: Low-pass filters are used in smoothing circuits to remove unintended AC parts in a rectifier.
• Question 25 : Impedance is minimum at resonance in an RLC series circuit.
• Question 26: Phase angle between inductor and capacitor voltages in an RLC series circuit is 180 degrees.
• Question 27: Peak voltage of a signal on a multimeter is shown.
• Question 30: Voltage on the secondary is 30V.
• Question 33: Induced voltage in a coil is proportional to the rate of change of magnetic flux.
• Question 37: Centrifugal switch in a single-phase induction motor is used to improve starting performance and cut off starting winding.
• Question 41: Turns ratio in a transformer is calculated by N1/N2.
• Question 44: At resonance in RLC circuit, total reactance and resistance are equal. The current flowing is maximum.
• Question 45: Shading coils in a shaded-pole motor are used to produce a rotating magnetic field.
• Question 46: Field winding in a large synchronous machine is placed on the rotor.
• Question 47: Repetition of a variable quantity at equal intervals is called a cycle.
• Question 53: The sum of resistance and reactance is called Impedance.
• Question 54: Units of capacitive reactance is Ohms.
• Question 55: Impedance is 115 Ohms.
• Question 56: Filters that let all frequencies pass except for a particular frequency band are called Band-Stop Filters.
• Question 57: Rms current if the frequency is doubled is 6.0 A.
• Question 60: Power factor in an AC circuit is calculated as real power / apparent power
• Question 62: Inductive reactance: XL = 2πfL
• Question 69: Total resistance of a circuit with resistance, capacitive reactance and inductive reactance is impedance
• Question 70: Low-pass filter passes frequencies below the cutoff frequency.
• Question 71: The magnetic field produced by an AC current is a dynamic magnetic field.
• Question 77: Graph showing characteristics of a series circuit is shown.
• Question 78: Filter shown in the figure is a low pass filter.
• Question 88: AC generator and transformer power is measured in Volt-Ampere (VA)
• Question 91: Impedance is calculated with R, XL and XC
• Question 92: Transformers work with AC current because AC produces a changing magnetic field.
• Question 93: Copper losses in a transformer are also known as variable loss
• Question 94: If an electric bulb is connected to an AC source, the voltage and current are in phase.
• Question 97: Electromagnetic Induction is the process of inducing an emf with a change in magnetic flux.
• Question 98: At the same voltage level, a higher frequency results in smaller components.
• Question 99: A transformer with a higher secondary voltage than the primary voltage is considered a step-up transformer.
• Question 100: Phase angle between capacitive voltage and inductive voltage in a series circuit is 180 degrees
• Question 101: Duration of one cycle is called period.
• Question 102: Average power dissipated in an ideal inductor is 0.
• Question 104: Graph reflects apparent power.
• Question 105: Step up transformer ratio is greater than 1.
• Question 106: Transformer reducing voltage is called a step-down transformer
• Question 107: RMS value of sine wave with peak value of 354 V is 250 V.
• Question 113: Maximum instantaneous value is peak value.
• **Question 115:**Secondary power of an ideal transformer with 2:1 voltage ratio and 100 W primary power is 50 W.
• Question 117: Current in an AC resistor circuit is in phase with the voltage.
• Question 121: Current lags the voltage by 90° in an inductor circuit.
• Question 122: If the frequency doubled, the capacitive reactance is half the original value.
• Question 124: Self-induced voltage in a coil is called back emf.
• Question 125: A single-phase induction motor is a self-starting motor.
• Question 129: if applied voltage is 400 V and capacitive reactance is 800 ohms, current is 0.5A.
• Question 132: Copper loss sum of hysteresis and eddy current losses are constant loss.
• Question 134: Average value of alternating current in a full sinusoidal cycle is zero.
• Question 136: A filter significantly attenuating frequencies below a cutoff frequency and passing above it is a high-pass filter.
• Question 137: Alternating current is an electric current whose direction and magnitude change periodically.
• Question 138: Lenz's law states that the direction of an induced current is always such as to oppose the change that produced it.
• Question 140: If frequency of AC increases, the inductive reactance increases, which leads to more opposition to the current flow.
• Question 141: Reactance.
• Question 142: Alternating voltage is represented by V(t) = Vm sin(wt).
• Question 143: The capacitor in the capacitor start induction run ac motor is connected in series with starting winding.
• Question 144: RMS value is the effective DC value of alternating current
• Question 145: At 30 HZ, voltage leads current because XC (capacitive) is less than XL (inductive)
• Question 146: A capacitor blocks DC current.