The arc across a switch when it open an RL circuit is a result of the
Large self-induced voltage across L
Long time constant
Low resistance of the open switch
Surge of resistance
Correct Answer :
A. Large self-induced voltage across L
Related Questions
What is the reciprocal of quality factor?
Power factor
Reactive factor
Dissipation factor
1/Q factor
Which of the following describes the action of a capacitor?
Stores electrical energy
Opposes changes in current flow
Creates a dc resistance
Converts ac to dc
If a capacitor is rated for 200V dca what is its effective ac working voltage?
50 V
100 V
200 V
400 V
Which of the following is the statement of Ohm�s law?
Electric current is directly proportional to both voltage and resistance
Electric current varies directly as the voltage and inversely as the resistance
Electrical power is directly proportional to the resistance and inversely as the current squared
Electrical power is directly proportional to both voltage squared and the resistance
For a series circuita the higher the quality factor
The greater the bandwidth
The narrower the passband
The broader the resonance curve
The wider the passband
When voltage is applied across a ceramic dielectric the electrostatic field p roduced is 50 times greater than air dielectric. The dielectric constant of ceramic therefore is
Loop currents should be assumed to flow in which direction
Straight
Clockwise
Counter-clockwise
Either B or C arbitrarily selected
What can be used to estimate resonant frequency and to find reactance at any frequency for any value of capacitor or inductor?
Smith chart
Reactance chart
Impedance chart
Resonance chart
A switch designed to have low capacitance between its terminal when open.
LOCAP switch
AntiLOCAP switch
Anticapacitance switch
Capacitance switch
At what frequency will the current in a series RLCcircuit reach its maximum value for an applied voltage of 15 V with R = 500 a L = 100 H and C= 0.001 F?
503 kHz
403 kHz
603 kHz
303 kHz
What value of R is needed with a 0.05 F Cfor an RCtime constant of 0.02 s?
400 M
400 G
400 k
The temperature coefficient of resistance of electrolytes is
Negative
Positive
Zero
Infinite
In a circuita an active element is one which
Supplies energy
Receives energy
Both supplies and receives energy
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An open inductor has
Zero resistance and infinite inductance
Infinite resistance and zero inductance
Infinite resistance and infinite inductance
Zero resistance and zero inductance
A law which states that when a constant electromotive force is applied to a circuit consisting of a resistor and capacitor connected in seriesa the time taken for the potential on the plates of the capacitor to rise to any given fraction of its final value depends only on the product of capacitance and resistance.
Child�s law
CR law
Coulomb�s law
Debye T3 law
The usual load of a dc circuit is a/an
Resistor
Capacitor
Inductor
Both inductor and capacitor
Electric energy refers to
Volt divided by coulomb
Voltampere
Volt-coulomb
Watt divided by time
Resistor with colored bands in the body
Wire-wound resistor
Carbon-composition resistor
Potentiometer
Rheostat
The curve between current and frequency is termed as
Voltage curve
Gain curve
Power curve
Resonance curve
In a complex resistance-reactance planea XLis represented
By an axis opposite the R axis
By an axis perpendicular to the XC axis
By an axis opposite the XCaxis
By an axis parallel to the R axis
The power factor of a circuit is equal to
RZ
XC/Z
XL/Z
R/Z
What is the rms value of a square wave?
Equals its peak value
Equals its peak-to-peak value
Peak divided by square root of two
Peak divided by pi
When two pure sine waves of the same frequency and the same amplitude which are exactly 180� outof-phase are added togethera the result is
A wave with twice the amplitude
A wave with half the amplitude
Zero signal
A wave with twice the frequency
If three 9 mH inductors are connected in parallel without mutual inductance then the total i nductance is
3 mH
9 mH
27mH
18 mH
Kirchhoff�s laws (KCL and KVL) are applicable to
DCcircuits
ACcircuits
DC as well as AC circuits
Passive networks alone
A series RL circuit has R of 10 and XL of 5 a its impedance in rectangular form is given by
10 +j 5
10 + j 10
10 ± j 5
10 ± j 10
An impedance given by 90 -45� is a/an ___ impedance.
Inductive
Conductive
Resistive
Capacitive
Delta to wye or wye to delta transformation technique is applied to a ___ network.
One-terminal
Two-terminal
Three-terminal
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The temperature-resistance coefficient of pure gold is
Effects of capacitance
It opposes any change in the amount of voltage
Voltage is lagged behind the current by a quarter cycle
Electric energy is stored in the capacitor in the form of electrostatic field
All of the above