What dielectric is generally employed by a variable capacitor?
Mica
Air
Electrolyte
Ceramic
Correct Answer :
B. Air
Related Questions
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
It is impossible to change the voltage across a capacitor instantlya as this would produce ___ current.
Infinite
Zero
Low
High
What is the conductance of a circuit having three 10 resistors in parallel?
0.3 S
3.33 S
0.33 S
30 S
For a linear circuita ___ voltage or current is used to calculate average power.
Rms
Peak
Average
Instantaneous
Delta to wye or wye to delta transformation technique is applied to a ___ network.
One-terminal
Two-terminal
Three-terminal
Complex
In a series circuit with unequal resistances the
Highest R has the highest V
Lowest R has the highest V
Lowest R has the highest I
Highest R has the highest I
How many degrees of phase represents one full cycle?
What is a rotating vector whose projection can represent either current or voltage in an ac circuit?
Polar diagram
Scalar quantity
Velocity
Phasor
An inductor carries 2 A dc. If its inductance is 100 Ha then what is its inductive reactance?
Zero
1.3 k
The charging of a capacitor through a resistance obeys
Exponential law
Logarithmic law
Linear law
Square law
In calculating maximum instantaneous power ___ voltage or current is used.
Peak
Average
Rms
Instantaneous
What is the total resistance of a two equal valued resistors in series?
The difference of both
The product of both
Twice as one
The sum of their reciprocals
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
Which is considered as the effect of a dielectric material?
Increasing capacitance
Decreasing capacitance
Reducing the working voltage
Increasing the distance between the plates
Points to be considered in choosing a capacitor
Working voltage
Type of dielectric
Capacitance
All of the above
The superposition theorem is used when the circuit contains
Reactive elements
Active elements
Number of voltage sources
Single voltage source
The ___ of an alternating quantity is defined as the fractional part of a period or cycle through which the quantity has advanced from selected origin.
Phase
Frequency
Amplitude
Waveform
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
If a coil has a Q of 10a it means that
The energy stored in the magnetic field of the coil is 10 times the energy wasted in its resistance
The energy wasted in its resistance is 10 times the energy stored in the magnetic field of the coil
It is a low Q coil
It is a high Q coil
An inductive load always has a ___ power factor
Leading
Lagging
Zero
Unity
Which of the following elements is active?
Resistor
Inductor
Capacitor
Ideal voltage source
Which factor does not affect resistance?
Length
Resistivity
Cross-sectional area
Mass
What is the resonant frequency of a circuit when L of 25 microhenrys and C of 10 picofarads are in parallel?
10.1 kHz
10.1 MHz
101 MHz
101 kHz
When capacitors are connected in seriesa the total capacitance is
Smaller than the smallest capacitor
Smaller than the largest capacitor
Greater than any of the capacitor
Greater than the largest capacitor
Electron flow assumes charges flow from
Negative to positive
Negative to negative
Positive to negative
Positive to positive
The ratio of maximum value to the effective value of an alternating quantity is called
Form factor
Peak factor
Dynamic factor
Leakage factor
What dielectric is generally employed by a variable capacitor?
Mica
Air
Electrolyte
Ceramic
In dividing or multiplying phasor quantitiesa ___ form is used.
Polar
Rectangular
Trigonometric
Exponential
What does a capacitor store?
Voltage
Charge
Current
Power
What is the form factor of a triangular wave?