In a pure capacitancea
Current leads voltage by 90�
Current leads voltage by 180�
Current lags voltage by 90�
Current lags voltage by 180�
Correct Answer :
A. Current leads voltage by 90�
Related Questions
In an ac circuita the power dissipated as heat depends on
Impedance
Capacitive reactance
Resistance
Inductive reactance
What is the half-power bandwidth of a parallel resonant circuit which has a resonant frequency of 3.6 MHz and Q of 218?
1.65 kHz
16.5 MHz
16.5 kHz
165 kHz
Which of the following capacitors has the highest cost per F?
Plastic
Air
Mica
Electrolytic
Of the equivalent combination of unitsa which one is not equal to watt?
2/V
AV
A2
J/s
For a triangular and sawtooth waveform the rms voltage or current equals
0.707times peak value
0.577 times peak value
0.577times average value
0.707times rms value
The impedance in the study of electronics is represented by resistan
Inductance
Capacitance
Inductance and capacitance
Reactance
For a parallel ACcircuita ___ is used as a reference phasor.
Voltage
Power
Current
Resistance
An alloy composed of 84 % coppera 12 % manganese and 4 % nickel.
Manganin
Constantan
Nichrome
German silver wire
Which of the following is not considered a physical factor affecting resistance?
Length
Material type
Temperature
Cross-sectional
What does a capacitor store?
Voltage
Charge
Current
Power
If one resistance in a series connection is opena then
The current is zero in all the other resistances
The current is maximum in all the other resistances
The voltage is zero across the open resistance
The voltage is infinite across the open resistance
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
What is the efficiency under the conditions of maximum power transfer?
Which statement is true?
A series resonant circuit is of high impedance
A parallel resonant circuit is of low impedance
A series resonant circuit is inductive if it operates at a frequency higher than the resonant frequency
A parallel resonant circuit is inductive if it operates at a frequency higher than the resonant frequency
A capacitive load always has a ______ power facto
Leading
Lagging
Zero
Unity
The mutual inductance between two coils is ___ the reluctance of magnetic path.
Directly proportional to
Inversely proportional to
Independent to
Equal to
If an emf in circuit A produces a current in circuit Ba then the same emf in circuit Bproduces the same current in circuit ? this theorem is known as
Maximum power transfer theorem
Millman�s theorem
Reciprocity theorem
Norton�s theorem
The current is ____ times the maximum current at half-power points of a resonance curve.
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 series-parallel combination of identical resistors will
Increase the power rating compared with one resistor alone
Increase the voltage rating compared with one resistor alone
Reduce the voltage rating compared with resistor alone
Result in an expensive circuit
A trigger circuit consisting of a capacitor of 0.01 F is connected in series with a resistor. If the circuit requires 100 Vdcto operatea determine the value of the resistor when time constant is 0.009s.
900 k
900 M
900 G
What is the purpose of a load in an electric circuit?
To increase the circuit current
To decrease the circuit current
To utilize electrical energy
To make the circuit complete
What determines the magnitude of electric current?
The rate at which electrons are produced
The type of material used
The current carrying capacity of the circuit
The rate at which electrons pass a given point
The value of temperature coefficient ( ) is dependent upon
The nature of material and temperature
The length of material
The cross-sectional area of the material
The volume of the material
What refers to such work at very low temperaturesa near absolute zero?
Cryogenics
Superconductivity
Subsonic
Thermionic
What is the peak factor of a triangular wave?
The power factor of a circuit is equal to
RZ
XC/Z
XL/Z
R/Z
In a complex number 5 + j 10a 10 is called ___ part.
Imaginary
Real
Conjugate
Integer
What is a closed path made of several branches of the network called?
Junction
Node
Terminal
Loop
The resistance of an insulator ___ when its temperature is increased.
Decreases
Remains the same
Increases
Varies