A wire of one kilometre length has a resistance of 20 . If the length is halveda then the new resistance is ___ the original resistance.
Half
Twice
One-fourth
Three times
Correct Answer :
A. Half
Related Questions
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
Which of the following is neither a basic physical law nor deliverable from one?
Ohm�s law
Coulomb�s law
Kirchhoff�s first law
Kirchhoff�s second law
What is the total capacitance of 10 capacitorsa each of 20 F in series?
200 F
2 F
100 F
0.5 F
What is the hot resistance of a 100 Wa 220 V incandescent lamp?
What is a closed path made of several branches of the network called?
Junction
Node
Terminal
Loop
The usual load of a dc circuit is a/an
Resistor
Capacitor
Inductor
Both inductor and capacitor
Electric energy refers to
Volt divided by coulomb
Voltampere
Volt-coulomb
Watt divided by time
Which of the following represents the energy stored in a cap
CV2/2
2Q2/C
C2/V
CV
If two equal resistances connected in series across a certain supply are now connected in parallel across the same supplya the power produced will be _____ that of series connection
One-half
One-fourth
Two times
Four times
The resistance of an insulator ___ when its temperature is increased.
Decreases
Remains the same
Increases
Varies
An intermittent and non-symmetrical alternating current like that obtained from the secondary winding of an induction coil
Faradic current
Transient ac current
Inductive current
Capacitive current
Which factor does not affect resistance?
Length
Resistivity
Cross-sectional area
Mass
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
In Norton�s theorema the short circuit current is obtained by
Opening the load terminals
Shorting the load terminals
Opening the voltage source
Shorting the voltage source
The charging of a capacitor through a resistance obeys
Exponential law
Logarithmic law
Linear law
Square law
What is the most convenient way of achieving large capacitance?
By using multiplate construction
By using air as dielectric
By decreasing distance between plates
By using dielectric of low permittivity
Which statement is true?
A series resonant circuit is of high impedance
A parallel resonant circuit is of low impedance
A series resonant circuit is inductive if it operates at a frequency higher than the resonant frequency
A parallel resonant circuit is inductive if it operates at a frequency higher than the resonant frequency
For multi-plate capacitora capacitance is proportional to
Number of plates less one(n ± 1)
Number of plates plus one(n + 1)
Number of plates less two(n - 2)
Number of plates (n)
The Q-factor of a series resonant circuit is also known as
Current magnification factor
Voltage magnification factor
Load factor
Leakage factor
If three 100-pF capacitors are connected in seriesa then the total capacitance is
300 pF
100 pF
50 pF
33.3 pF
A lead conductor has a resistance of 25 at 0 �C. Determine its resistance at -30 �C
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
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
For a series ACcircuita ___ is not used as a reference phasor.
Voltage
Impedance
Current
Conductance
Which of the following is not considered a physical factor affecting resistance?
Length
Material type
Temperature
Cross-sectional
A capacitive load always has a ______ power facto
Leading
Lagging
Zero
Unity
If a certain circuit has a current that is lagging the voltage by 45�a then it displays
Pure inductive reactance
Resistance and capacitance reactance
Resistance and inductive reactance
Pure capacitive reactance
Permeability is otherwise known as
Magnetic conductivity
Magnetic susceptibility
Electric conductivity
Electric susceptibility
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
Why are inductance and capacitance not relevant in a dc circuit?
Because it is a simple circuit
Because dc circuits require only resistance as load
Because they do not exist in a dc circuit
Because frequency of dc is zero