Which of the following elements is active?
Resistor
Inductor
Capacitor
Ideal voltage source
Correct Answer :
D. Ideal voltage source
Related Questions
The electric field strength between capacitor plates has a unit
Volts per meter
Volts per mil
Amperes per meter
Amperes per mil
The Q-factor of a parallel resonant circuit is also known as
Current magnification factor
Voltage magnification factor
Load factor
Leakage factor
Series resonance occurs when
XL= XC
XL= R
Z = R
Both A and C
What is the hot resistance of a 100 Wa 220 V incandescent lamp?
What is the cross-sectional are of a conductor whose diameter is 0.001 inch?
One micron
One angstrom
One steradian
One circular mil
What does a capacitor store?
Voltage
Charge
Current
Power
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
Which of the following dielectric materials makes the highest-capacitance capacitor?
Air
Barium-strontium titanite
Mica
Electrolyte
A capacitor opposes change in
Voltage
Current
Voltage and current
Neither voltage nor current
The reciprocal of a complex number is
A complex number
A real number
An imaginary number
A whole number
The hot resistance of an incandescent lamp is about ___ times its cold resistance.
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
A lead conductor has a resistance of 25 at 0 �C. Determine its resistance at -30 �C
What is the most common non-sinusoidal waveform?
Square wave
Triangular wave
Trapezoidal wave
Sawtooth wave
The maximum power transfer theorem is used in
Power system
Electronic system
Refrigeration
Air conditioning
The mutual inductance between two coils is ___ the reluctance of magnetic path.
Directly proportional to
Inversely proportional to
Independent to
Equal to
An inductor carries 2 A dc. If its inductance is 100 Ha then what is its inductive reactance?
Zero
1.3 k
Which is considered as the effect of a dielectric material?
Increasing capacitance
Decreasing capacitance
Reducing the working voltage
Increasing the distance between the plates
Which of the following does not refer to electrical energy?
Volt-ampere
Joule
Watt-second
Volt-coulomb
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
Why are inductance and capacitance not relevant in a dc circuit?
Because it is a simple circuit
Because dc circuits require only resistance as load
Because they do not exist in a dc circuit
Because frequency of dc is zero
Which of the following is a disadvantage of a wire-wound resistor?
It has reactance in radio-frequency circuits
It cannot handle much power
It draws a large amount of current
It cannot handle high voltage
What is the most convenient way of achieving large capacitance?
By using multiplate construction
By using air as dielectric
By decreasing distance between plates
By using dielectric of low permittivity
When two in-phase sine waves that have identical frequency and amplitude are added togethera then the result is a sine wave with ___ the amplitude of either.
Half
Twice
Four times
One-fourth
In an inductive coila the rate of rise of current is maximum
Near the final maximum value of current
At midvalue of current
At half-power points
After one time constant
The wavelength of an alternating waveform depends upon the ___ of the variation.
Period
Number
Frequency
Amplitude
The power factor of a certain circuit in which the voltage lags behind the current is 80 %. To increase the power to 100 %a it is necessary to add ___ to the circuit.
Inductance
Capacitance
Resistance
Impedance
What is considered as the most important value of a sine wave?
Effective value
Peak value
Average value
Instantaneous value
An inductance of 1 mH is
0.001 H
0.01 H
0.0001 H
0.10 H
Which of the following is a common material used in wire-wound resistors?
Manganin
Carbon
Bronze
German silver wire