The temperature coefficient of resistance of electrolytes is
Negative
Positive
Zero
Infinite
Correct Answer :
A. Negative
Related Questions
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
A capacitor is basically constructed of
Two conductors separated by a dielectric
Two dielectric separated by a conductor
Conductors and dielectric
Conductors and semiconductors
The symbol Q refers to
Resonance quotient
Quality factor
Power quotient
Qualification test
Metal tin becomes superconductor at approximately
6 K
3.7 K
5 K
4.7K
A switch designed to have low capacitance between its terminal when open.
LOCAP switch
AntiLOCAP switch
Anticapacitance switch
Capacitance switch
An impedance given by 90 -45� is a/an ___ impedance.
Inductive
Conductive
Resistive
Capacitive
A resistor wound with a wire doubled back on itself to reduce the inductance.
Bifilar resistor
Wire-wound resistor
Anti-inductive resistor
Bleeder resistor
A linear circuit is one whose parameters
Change with change in voltage
Change with change in current
Do not change with voltage and current
Change with change in voltage and current
What is the temperature coefficient of the resistance Eureka?
Infinity
Negative
Almost zero
Positive
What is expected when two 20 k a 1 watt resistor in parallel are use instead of one 10 k a 1 watt?
Provides higher current
Provides less power
Provides more power
Provides wider tolerance
Norton�s theorem is what form of an ac equivalent circuit?
Voltage
Current
Both voltage and current
Neither voltage nor current
For a carbon composition resistora typical resistance values range from
2.7 to 22 M
1000 to 10000
10 to 10 M
2.7 to 2.7G
In an ac circuit with a resistive branch and an inductive branch in parallela the
Voltage across the inductance leads the voltage across the resistance by 90°
Resistive branch current is 90° out of phase with the inductive branch current
Resistive and inductive branch currents have the same phase
Resistive and inductive branch currents are 180° outof-phase
If resonant frequency is 10 kHz and quality factor is 50a then
Bandwidth is 200 Hz
XL= is 50a000
R is 50
XC= is 50a000
According to Gauss theorema flux can be equated to
Charge
Field intensity
Current
Voltage
What is the resonant frequency of a circuit when L of 3 microhenrys and C of 40 picofarads are in series?
14.5 kHz
145 MHz
14.5 MHz
145 kHz
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
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
Which of the following capacitors is suitable for dc filter circuits?
Mica
Ceramic
Paper
Electrolytic
The resistance of an insulator ___ when its temperature is increased.
Decreases
Remains the same
Increases
Varies
What fusion of elements is without chemical action between them?
Mixture
Compound
Alloy
Ionization
A trimmer is a variable capacitor in which capacitance is varied by changing the
Number of plates
Dielectric
Distance between plates
Plate area
An open resistor when checked with an ohmmeter reads
Zero
Infinite
High but within the tolerance
Low but not zero
The charging of a capacitor through a resistance obeys
Exponential law
Logarithmic law
Linear law
Square law
Resistor with colored bands in the body
Wire-wound resistor
Carbon-composition resistor
Potentiometer
Rheostat
In an ac circuit with XL and R in seriesa the
Voltages across R and XL are in phase
Voltage across R lags the voltage across XLby 90°
Voltages across R and XL are 180° outof-phase
Voltage across R leads the voltage across XLby 90°
Liquids that are good conductors because of ionization are called
Electrolytic
Bases
Acid
Electrolytes
Which of the following describes the action of a capacitor?
Stores electrical energy
Opposes changes in current flow
Creates a dc resistance
Converts ac to dc
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 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