A neon glow lamp used as a night light ionizes at approximately
70 V
80 V
90 V
100 V
Correct Answer :
A. 70 V
Related Questions
If a multiplate capacitor has 10 platesa each of area 10 cm2a then
10 capacitors will be in parallel
10 capacitors will be in series
9 capacitors will be in parallel
9 capacitors will be in series
Which of the following dielectric materials makes the highest-capacitance capacitor?
Air
Barium-strontium titanite
Mica
Electrolyte
Capacitance increase with
Larger plate area and less distance between plates
Larger plate area and greater distance between plates
Smaller plate area and less distance between plates
Higher values of applied voltage
Form its definitiona the unit of electric fielda is the N/C and equivalent unit of is the
V(m)2
V(m)
V/m2
V/m
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
Property of an electric circuit that dissipates electric energy
Reactance
Impedance
Resistance
Conductance
What is the reciprocal of capacitance?
Reluctance
Susceptance
Elastance
Conductance
Which of the following elements is active?
Resistor
Inductor
Capacitor
Ideal voltage source
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
A capacitance of 6 ��F means
6 pF
6 nF
6 fF
6 aF
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
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
The average value of a triangular or sawtooth wave is _____ times its peak value.
Liquids that are good conductors because of ionization are called
Electrolytic
Bases
Acid
Electrolytes
A resistor wound with a wire doubled back on itself to reduce the inductance.
Bifilar resistor
Wire-wound resistor
Anti-inductive resistor
Bleeder resistor
What capacitance exists not through design but simply because two conducting surfaces are relatively close to each other?
Surge
Stray
Natural
Normal
In an ac circuita the power dissipated as heat depends on
Impedance
Capacitive reactance
Resistance
Inductive reactance
Which of the following does not generally affect the value of a capacitor?
The dielectric material used
The surface area of the plates
The thickness of the dielectric
The voltage applied to the plate
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
The internal resistance of an ideal voltage source is
Infinite
Equal to the load resistance
Zero
To be determined
A capacitor of 0.5 F charged to 220 V is connected across an uncharged 0.5 F capacitor. What is the voltage across each capacitor?
220 V
150 V
110 V
22 V
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
What is the reading of an ohmmeter for a shorted capacitor?
Zero
Infinity
k
M
When frequency of an ac wave decreasesa the value of XLin a coil
Approaches zero
Gets larger positively
Gets larger negatively
Stays constant
A 0.09 microfarad capacitor is charged to 220 volts. How long in milliseconds will it discharged resistor has a resistance of 20a000 ohms?
Which of the following is the peakiest?
Square wave
Sinusoidal wave
Triangular wave
Rectangular wave
A coil of inductance L has an inductive reactance of XLin an ac circuit in which the effective current is I. The coil is made from a superconducting material. The rate at which power is dissipated in the coil is
I2XL
IXL
IXL2
What is the peak factor for alternating current or voltage varying sinusiodally?
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
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