The reason why alternating current can induce voltage is
It has high peak value
It has a stronger magnetic field than direct current
It has a constant magnetic field
It has a varying magnetic field
Correct Answer :
D. It has a varying magnetic field
Related Questions
Which of the following represents the energy stored in a cap
CV2/2
2Q2/C
C2/V
CV
Which of the following is a preferred resistor value?
43a000
54a321
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 does a capacitor store?
Voltage
Charge
Current
Power
Which statement is true about a passive circuit?
A circuit with neither a source of current nor a source of potential difference
A circuit with a voltage source
A circuit with a current source
A circuit with only resistance as a load
In liquids and gasesa ionization current results from a flow of
Positive or negative ions
Free electrons
Ions that are lighter in weight than electrons
Protons
Electron flow assumes charges flow from
Negative to positive
Negative to negative
Positive to negative
Positive to positive
In a rectangular wavea the form factor is
VL= VCin a series RLCcircuit when
The value of the impedance is minimum
The power factor is zero
The current leads the total voltage by 90�
The total voltage is zero
An inductance of 1 mH is
0.001 H
0.01 H
0.0001 H
0.10 H
If three 100-pF capacitors are connected in seriesa then the total capacitance is
300 pF
100 pF
50 pF
33.3 pF
Which of the following is a way of decreasing mutual inductance?
Moving the coils closer
Moving the coils apart
Decreasing the number of turns of either coil
Increasing the number of turns of either coil
High resistance values are a consequence of the ___ of the film.
Thickness
Length
Thinness
Area
When resistance are connected in parallela the total resistance is
Less than the smallest resistance in the connection
Greater than the smallest resistance in the connection
Between the smallest and greatest resistance in the connection
Increasing and decreasing depending upon the supply voltage
What theorem is generally used in the analysis of vacuum tubes?
Superposition theorem
Millman�s theorem
Thevenin�s theorem
Norton�s theorem
When capacitors are connected in parallela the total capacitance is
Greater than the largest capacitor
Smaller than the largest capacitor
Smaller than the smallest capacitor
Greater than the smallest capacitor
What is the most common non-sinusoidal waveform?
Square wave
Triangular wave
Trapezoidal wave
Sawtooth wave
The internal resistance of an ideal current source is
Infinite
Zero
Equal to the load resistance
To be determined
A real current source has
Infinite internal resistance
Zero internal resistance
Large internal resistance
Small internal resistance
Which of the following has negative temperature coefficient?
Carbon
Nickel
Brass
Constantan
If the capacitance of mica capacitor is 5 times the capacitcitora then the relative permittivity of mica is
A capacitor is basically constructed of
Two conductors separated by a dielectric
Two dielectric separated by a conductor
Conductors and dielectric
Conductors and semiconductors
A series RLCcircuit consists of a 10 resistor in series with L = 10 Ha and C= 100 F. Determine a new value of Ia for which the resonant frequency is one ±half the original value.
40 H
40 mH
40 pH
40 nH
³Any resistance R in a branch of a network in which a current I is flowing can be replaced by a voltage equal to IR�. This states
Compensation theorem
Reciprocity theorem
Millman�s theorem
Superposition theorem
The current is ____ times the maximum current at half-power points of a resonance curve.
A factor that states how much the resistance changes for a change in temperature?
Resistivity
Specific resistance
Coefficient of temperature change
Temperature coefficient of resistance
Which of the following combination of length and cross-sectional area will give a certain volume of copper the least resistance?
2L and1/2 A
Does not matter because the volume of copper remains the same
L and A
½ L and 2 A
Voltage resonance means
Series resonance
Parallel resonance
Current magnification
Gain magnification
Rationalizing the denominator of a complex number means
Eliminating the j component in the denominator
Adding j component in the denominator
Eliminating the j component in the numerator
Adding j component in the numerator
At what frequency will an inductor of 5mH have the same reactance as a capacitor of 0.1 F?
7.12 kHz
7.12 Hz
7.12MHz
7.12 GHz