Q.1
What will happen, if we connect capacitor to DC Supply.
  • It allows DC
  • It blocks DC
  • t rectifies
  • None of these
  • Hint: Diode is unidirectional and uncontrolled device. In rectifier circuit, diode use as a switch to convert ac to dc for rectification purpose.
Q.2
An inductor of inductance 22.0 mH is connected to an a.c. supply with frequency f. If the reactance of the inductor isΩ, what is the value of f?
  • 1.45 ×103 \times10^3\ ×103 Hz
  • 3.00 \times10^3\×103 Hz
  • 4.77 \times10^3\×103 Hz
  • 7.16 \times10^3\×103 Hz
Q.3
The highest value reached by the voltage or current in one cycle is called:
  • Instantaneous value
  • Peak to peak value
  • Peak value
  • Root mean square value
Q.4
What is alternating current
  • the process of inducing an emf (voltage) with a change in magnetic flux
  • Electric currents whose direction and magnitude change periodically depending on time are called alternating current
  • Steady current which delivers the same average power as the a.c. to a resistive load.
  • Making a rectified current more steady (or smooth) by placing a capacitor in parallel with the resistor​
Q.5
The electricity in our house is
  • AC
  • DC
  • BC
  • AD
Q.6
An electric current that continually reverses direction over time is known as a(n)
  • direct current
  • alternating current
  • simple current
Q.7
Which of the following general equations represent AC current
  • I=Iosin⁡(2πft)I=I_o\sin\left(2\pi ft\right)I=Io​sin(2πft)
  • I=Iosin⁡(2πft)I=I_o\sin\left(\frac{2\pi}{f}t\right)I=Io​sin(f2π​t)
  • I=Iocos⁡(ωt)I=I_o\cos\left(\omega t\right)I=Io​cos(ωt)
  • I=Iocos⁡(t)I=I_o\cos\left(t\right)I=Io​cos(t)
Q.8
Which is the correct equation of  VrmsV_{rms}Vrms​ ?
  • Vrms=VoV_{rms}=V_oVrms​=Vo​
  • Vrms=2VoV_{rms}=\frac{\sqrt{2}}{V_o}Vrms​=Vo​2​​
  • Vrms=Vo2V_{rms}=\frac{V_o}{\sqrt{2}}Vrms​=2​Vo​​
  • Vrms=Vo2sin⁡ 2tV_{rms}=\frac{V_o}{\sqrt{2}}\sin\ 2tVrms​=2​Vo​​sin 2t
Q.9
Rms value of ac current is the equivalent direct current which produces
  • the same average energy
  • the same power dissipation
  • the same rate of current flow
  • the same rate of power use
Q.10
A pure resistor is connected to an a.c. source where its current is given by I=5.0 sin 628t. Which of the following statements is not true about the circuit?
  • The peak value of current flowing through the resistor is 5.0 A
  • The root mean square current flowing through the resistor is 3.5 A
  • The frequency of the current flowing through across the resistor is 120 Hz
  • The equivalent direct current which gives the same average heating power in the resistor is 3.5 A
Q.11
A power supply has a peak value ofVolts sine wave, what is the effective dc voltage of this power supply?
  • 306 V
  • 433 V
  • 612 V
  • 220 V
Q.12
A heater is rated asV,kW. The valueV refers to
  • average voltage
  • r.m.s voltage
  • peak voltage
Q.13
The average current/ voltage value will not be zero only if it is
  • step up
  • rectified
  • amplified
  • intensified
Q.14
High potential voltage produced by three-phase generators commonly used in
  • filament
  • X-ray tube
  • transformer
  • anode
Q.15
The combination of resistance, capacitance and induntance is referred to
  • impedance
  • reactance
  • angular frequency
  • amplitude
Q.16
Voltage leads the current in an AC generators can be referred to
  • resistance
  • capacitance
  • inductance
Q.17
The resistor in an AC will cause
  • no phase difference
  • V lead I
  • I lead V
  • I lags V
Q.18
The effective voltage value is
  • 25%
  • 50%
  • 71%
  • 90%
Q.19
The distance of the waveform travel in one cycle is referred to
  • amplitude
  • wavelength
  • time
  • frequency
Q.20
In AC generator, maximum emf generated at an angle of
  • 0 and 90
  • 90 and 180
  • 90 and 270
  • 180 and 360
Q.21
AC generators works based on
  • Faraday's Law
  • Lenz Law
  • Newton's Law
  • electrostatic law
Q.22
AC generators used to produce alternating current by converting
  • kinetic energy into potential energy
  • potential energy into electrical energy
  • kinetic energy into electrical energy
  • electrical energy into kinetic energy
Q.23
The maximum instantaneous value measured from zero value is known as?
  • Peak value
  • Peak to peak value
  • Cycle
  • Period
Q.24
The repetition of a variable quantity, recurring at equal intervals, is known as ___________
  • Waveform
  • Instantaneous value
  • Cycle
  • Period
Q.25
The variation of a quantity such as voltage or current shown on a graph is known as ___________
  • Waveform
  • Peak value
  • Instantaneous value
  • Period
Q.26
Alternating voltage (V) is represented by the equation
  • V(t) = Vm eωt
  • V(t) = Vm sin ωt
  • V(t) = Vm cot ωt
  • V(t) = Vm tan ωt
Q.27
The unit of frequency is
  • Cycle
  • Cycle-second
  • Hertz/second
  • hertz
Q.28
A vector quantity has
  • Only magnitude
  • Only direction
  • Both (a) and (b)
  • none of these
0 h : 0 m : 1 s