A commercial alloy of aluminum nickela and iron with cobalta copper and titanium added to produce about 12 grades.
Alnico
Brass
Aluminum
Constantan
Correct Answer :
A. Alnico
Related Questions
Electric field intensity at a point due to a given charge ______ if the relative permittivity of the medium decreases.
decreases
remains unchanged
increases
b ecomes zero
Another term for corona discharge.
Lightning
Sparking
Aurora
Corona Effect
A factor used to correct for the electrostatic forces of the more distant ions in an ionic solid.
Avogadro's number
Planck's constant
Boltzmann's constant
Madelung constant
Which element has four valence electrons?
Conductor
Insulator
Semiconductor
Semi- insulator
A 200-watt lamp working for 24 hours will consume approximately _____ units.
One coulomb of charge consists of ________ electrons.
624× 10^16
62.4 × 10^16
6.24 × 10^16
0.624 × 10^16
Who discovered that a current-carrying conductor would move when placed in a magnetic field?
Michael Faraday
Andre Ampere
Hans Christian Oersted
Gustav Robert Kirchhoff
______ is an electromagnet with its core in the form of a close magnetic ring.
S olenoid
Paraboloid
Toroid
Cycloid
The resistance of a material is ____________ its area of cross-section.
directly proportional
independent of
inversely proportional to
equal to
The relation between absolute permittivity of air ( 0)a absolute p and velocity of light (c) is given by
0 0= c^2
0 0= c
1/ 0 0= c
1/ 0 0= c^2
A law relating between the magnetic and electric susceptibilities and the absolute temperatures which is followed b ferromagnetsa antiferromagnetsa non-polar ferroelectricsa antiferroelectrics and some paramagnets.
Curie's Law
Child's Law
CR Law
Curie-Weiss Law
Which of the following is used by temporary magnets as the magnetic material?
Hardened steel
Cobalt steel
Soft iron
Tungsten steel
The force which set ups or tends to set up magnetic flux in a magnetic circuit
Dynamic force
Electromotive force
Potential difference
Magnetomotive force
When the ferromagnetic substance is inserted in a current- carrying solenoida the magnetic field is
Greatly decreased
Greatly increased
Slightly decreased
Slightly increased
The evaporation of electrons from a heated surface is called
Radiation
Convection
Thermionic emission
Conduction
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 temperature coefficient of resistance of semiconductors is
positive
zero
negative
infinite
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
How many turns are needed to produce a magnetomotive force of 1000 A.t for a coil with 6 amperes?
6000 turns
600 turns
167 turns
67turns
One of the solid structures in which the position of the atoms or ions are predetermined
Crystalline solid
Amorphous solid
Polycrystalline solid
Poly amorphous solid
If on looking at any one end of a solenoid; the direction of current flow is found to be clockwise then the end under observation is a south pole. This is known as
Right hand rule
Left hand rule
Cork screw rule
End Rule
What is another name for relative permittivity?
Dielectric strength
Electric intensity
Potential gradient
Dielectric constant
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
All matters (gasa liquid and solid) are composed of
Neutrons
Particles
Electrons
Atoms
A 6- V battery is connected across a solenoid of 100 turns having a resistance of 2 ?a Calculate the number of ampere turns?
The lagging effect between flux density of the material and the magne
Permeance
Eddy current
Hysteresis
R eluctance
The electrons in the last orbit of an atom are called _______ electrons.
free
valence
bound
thermionic
__________ is a substance of whose molecules consist of the same kind of atom.
Mixture
Compound
Element
Isotope
When the current flowsa the magnetic field ��. conductor is in what direction?
The same as the current direction
Opposite the current direction
Omnidirectional
In the direction determined by the left hand rule
The temperature coefficient of resistance of insulators is
zero
negative
positive
infinite