Tungsten filament of bulbs has a hot resistance higher than its cold resistance due to its temperature coefficient which is
Positive
Negative
Zero
Infinite
Correct Answer :
A. Positive
Related Questions
The graph between an alternating quantity and time is called
Sine wave
Curve
Waveform
A plot
It is impossible to change the voltage across a capacitor instantlya as this would produce ___ current.
Infinite
Zero
Low
High
A capacitance of 0.05 F equals
0.05 x 106F
0.05 x 10-6F
0.05 x 10-12F
0.05 x 1012F
Two capacitors of capacitance 9 F and 18 F in series will have a total capacitance of
27 F
162 F
6 F
180 F
The Q-factor of a parallel resonant circuit is also known as
Current magnification factor
Voltage magnification factor
Load factor
Leakage factor
A 5 F capacitor charge to 5V has a stored charge equal to
1 c
5 c
25 C
200 c
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
If the inductance is decreaseda the impedance of the circuit containing a resistor a capacitor and an inductor connected in series to an ac source
Decreases
Increases
Decreases or increases
Decreasesa increases or remains the same
How many degrees of phase represents one full cycle?
What is the hot resistance of a 100 Wa 220 V incandescent lamp?
High resistance values are a consequence of the ___ of the film.
Thickness
Length
Thinness
Area
Thevenin�s theorem is what form of an equivalent circuit?
Current
Voltage
Both current and voltage
Neither current nor voltage
When two unequal values of resistors are connected in parallel across a dc sourcea greater current flows through the
Higher resistance
Lower resistance
Higher wattage resistance
Lower wattage resistance
The reason why electrical appliances are not connected in series.
Greater electrical power saving
Power loss is minimum
Appliances have different current ratings
All of the above
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
In a circuita a passive element is one which
Supplies energy
Receives energy
Both supplies and receives energy
Attenuates signal
If voltage across the plates of 2 F capacitor is increased by 4 Va then charge on the plates will
Decrease by 2 C
Increase by 2 C
Decrease by 4 C
Increase by 4C
A circuit whose parameters change with voltage or current.
Non-linear circuit
Linear circuit
Complex circuit
Passive circuit
What is the rms value of a square wave?
Equals its peak value
Equals its peak-to-peak value
Peak divided by square root of two
Peak divided by pi
What is the reading of an ohmmeter for a shorted capacitor?
Zero
Infinity
k
M
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 is the value of a carbon composition resistor with the following color code: Browna whitea orangea red
190 ; 10 %
19 k ; 2 %
19 k ; 20 %
1.9 k ; 2 %
A 0.09 microfarad capacitor is charged to 220 volts. How long in milliseconds will it discharged resistor has a resistance of 20a000 ohms?
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
The reciprocal of a complex number is
A complex number
A real number
An imaginary number
A whole number
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
Barium-strontium titanite dielectric material is also called
Ceramic
Polyster
Electrolytic
Bakelite
The presence of an electric current is made known by
Electric shock
Effects produced
Magnetic shock
Flashing
Two complex numbers or phasors are said to be conjugate if they
Differ only in the algebraic sign of their quadratic components
Differ only in the algebraic sign of their real components
Are equal in their real and quadrature components including alge
Are equal in their real components but differ in their quadrature components i ncluding algebraic signs.
The factor 0.707for converting peak to rms applies only to
Square waves
Triangle waves
Sawtooth waves
Sine waves