Q.1
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.2
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.3
The electricity in our house is
  • AC
  • DC
  • BC
  • AD
Q.4
An electric current that continually reverses direction over time is known as a(n)
  • direct current
  • alternating current
  • simple current
Q.5
Which of the following general equations represent AC current
  • $I=I_o\sin\left(2\pi ft\right)$
  • $I=I_o\sin\left(\frac{2\pi}{f}t\right)$
  • $I=I_o\cos\left(\omega t\right)$
  • $I=I_o\cos\left(t\right)$
Q.6
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.7
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.8
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.9
A heater is rated asV,kW. The valueV refers to
  • average voltage
  • r.m.s voltage
  • peak voltage
Q.10
The average current/ voltage value will not be zero only if it is
  • step up
  • rectified
  • amplified
  • intensified
Q.11
High potential voltage produced by three-phase generators commonly used in
  • filament
  • X-ray tube
  • transformer
  • anode
Q.12
The combination of resistance, capacitance and induntance is referred to
  • impedance
  • reactance
  • angular frequency
  • amplitude
Q.13
Voltage leads the current in an AC generators can be referred to
  • resistance
  • capacitance
  • inductance
Q.14
The resistor in an AC will cause
  • no phase difference
  • V lead I
  • I lead V
  • I lags V
Q.15
The effective voltage value is
  • 25%
  • 50%
  • 71%
  • 90%
Q.16
The distance of the waveform travel in one cycle is referred to
  • amplitude
  • wavelength
  • time
  • frequency
Q.17
In AC generator, maximum emf generated at an angle of
  • 0 and 90
  • 90 and 180
  • 90 and 270
  • 180 and 360
Q.18
AC generators works based on
  • Faraday's Law
  • Lenz Law
  • Newton's Law
  • electrostatic law
Q.19
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.20
The maximum instantaneous value measured from zero value is known as?
  • Peak value
  • Peak to peak value
  • Cycle
  • Period
Q.21
The repetition of a variable quantity, recurring at equal intervals, is known as ___________
  • Waveform
  • Instantaneous value
  • Cycle
  • Period
Q.22
The variation of a quantity such as voltage or current shown on a graph is known as ___________
  • Waveform
  • Peak value
  • Instantaneous value
  • Period
Q.23
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.24
The unit of frequency is
  • Cycle
  • Cycle-second
  • Hertz/second
  • hertz
Q.25
A vector quantity has
  • Only magnitude
  • Only direction
  • Both (a) and (b)
  • none of these
Q.26
A pure capacitor is connected to an AC power supply. In this circuit, the current
  • leads the voltage by 90°.
  • lags the voltage by 90°.
  • is in phase with the voltage.
  • none of the given answers
Q.27
Which is the correct equation of  $V_{rms}$ ?
  • $V_{rms}=\frac{V_o}{\sqrt{2}}\sin\ 2t$
  • $V_{rms}=V_o$
  • $V_{rms}=\frac{\sqrt{2}}{V_o}$
  • $V_{rms}=\frac{V_o}{\sqrt{2}}$
Q.28
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?
  • 3.00 \times10^3\×103 Hz
  • 4.77 \times10^3\×103 Hz
  • 7.16 \times10^3\×103 Hz
  • 1.45 $\times10^3$ Hz
0 h : 0 m : 1 s