The temperature coefficient of resistance of a conductor ______ with an increase in temperature.
increases
decreases
remains the same
becomes negative
Correct Answer :
B. decreases
Related Questions
A commercial alloy of aluminum nickela and iron with cobalta copper and titanium added to produce about 12 grades.
Alnico
Brass
Aluminum
Constantan
Bonding of atoms that is due to the force of attraction between positive ions and a group of negative ions
Ionic bond
Covalent Bond
Electrostatic Bond
Metallic bond
The magnetic potential in a magnetic circuit can be measured in terms of
Mmf
Emf
Farad
Coulomb
What is the reluctance of a magnetic path having a length of 2x 10^-3m and crosssectional area of 2.5 x 10^-3 m^2?
6366 A, t/Wb
6000 A, t/Wb
8x10^-3 A, t/Wb
0.8 A, t/Wb
The resistance of a material is ____________ its area of cross-section.
directly proportional
independent of
inversely proportional to
equal to
What is the practical unit of electrical energy?
Watt
Kilowatt-hour
Kilowatt-second
Megawathour
If you hold the conductor with right hand so that the stretched thumb points in the direction of the currenta then encircling fingers will give the direction of magnetic lines of force round the conductor. This is known as
Left hand cork screw rule
Right hand cork screw rule
Left hand rule
Right hand rule
The electric flux density is a ________ quantity.
phasor
vector
scalar
variable
The diameter of a hydrogen atom is approximately ______ cm.
1.1 x 10^-6
1.1 x 10^7
1.1 x 10^-8
1.1 x 10^-9
Magnetic intensity is a
Phasor quantity
Physical quantity
Scalar quantity
Vector quantity
Which of the following electric quantities is vector in character?
Field
Charge
Energy
Potential Difference
The relative permeability of a magnetic material is 10^5. What is its permeability?
4 × 10^5 H/m
4 × 10^-12 H/m
4× 10^-2 H/m
4 × 10^7H/m
If the number of valence electrons of an atom is less than 4a the substance is called
a conductor
a semiconductor
an insulator
a superconductor
One ampere- turn is equivalent to _____ gilberts
The ratio of the permeability of material to the permiabiity of air or vacuum.
Relative permeability
Relative permittivity
Relative conductivity
Relative reluctivity
The magnetic energy stored in an inductor is ______ current.
Directly proportional to
Inversely proportional to
Directly proportional to the square of
Inversely proportional to the square of
Electromotive force in a circuit
causes free electrons to flow
increases the circuit resistance
maintains circuit resistance
is needed to make the circuit complete
The force between two magnetic poles is _____ their poles strength.
equal to
directly proportional to
inversely proportional to
directly proportional to the square root of
The ability of a mechanically stressed ferromagnetic wire to recognize rapid switching of magnetization when subjected to a dc magnetic field.
Wartheim effect
Wiedemann effect
Wiegand effect
Edison effect
Electrons at the outer shell are called
Outer shell electrons
Inner shell electrons
Semiconductor electrons
Valence electrons
What revolves about the positive nucleus in a definite orbit?
Atom
Proton
Electron
Neutron
Define as that pole which when placed in air from a similar and equal pole repels it with a force of newtons
North pole
South pole
Unit pole
Magnetic pole
The force between two magnetic poles varies with the distance between them. The variation is ______ to the square of that distance.
Equal
Greater than
Directly proportional
Inversely proportional
The permeability of a material having a flux density of 5 Wb/m^2 is 10^-5 H/m. What is the value of magnetizing force?
5 × 10^-5 N/Wb
500 × 10^3 N/Wb
4 × 10^7N/Wb
4 × 10^7N/Wb
One weber of flux is equal to _______ magnetic lines of force.
10^6
10^10
4 × 10^7
10^8
It is the reciprocal of reluctance and implies the case of readiness with which magnetic flux is developed.
R esistance
Conductance
Permeance
I nductance
What determines the value of the temperature coefficient of resistance of a material?
length
cross-sectional area
volume
nature and temperature
What is the cgs unit of magnetomotive force?
Gilbert
Ampere- turn
Maxwell
Weber
The reluctance of a magnetic circuit varies with
length × area
area � length
length � area
length + area
Whenever a flux inking a coil or current changesa an emf is induced in it. This is known as
Joule's Law
Coulomb's Law
Faraday's first law of electromagnetic induction
Faraday's second law of electromagnetic induction