Permeability means
The conductivity of the material for magnetic lines of force
The magnetization test in the material after exciting field has been removed
The strength of an electromagnet
The strength of the permanent magnet
Correct Answer :
A. The conductivity of the material for magnetic lines of force
Related Questions
The direction of force o a current carrying conductor placed in a m found by
Cork screw rule
Fleming's left hand rule
Fleming's right hand rule
using a compass
The force between two magnetic poles is _____ the relative permeability of the medium.
directly proportional to
independent of
inversely proportional to
equal to
One weber of flux is equal to _______ magnetic lines of force.
10^6
10^10
4 × 10^7
10^8
Magnetic intensity is a
Phasor quantity
Physical quantity
Scalar quantity
Vector quantity
An atom or a group of atoms that carries a net electric charge.
Positive ion
Negative ion
Ion
Electron
Another term for corona discharge.
Lightning
Sparking
Aurora
Corona Effect
Defined as the ratio of the volume occupied by the atoms or ions in a unit cell divided by the volume of the unit cell and is used to measure the compactness of a crystal.
Atomic packing factor (APF)
Ionic Packing Ratio (IPR)
Atomic compacting factor (ACF)
Ionic compacting ratio (ICR)
The force acting on a pole of 5 Wb is 25 N. What is the intensity of the magnetic field?
5 N/Wb
25 N/Wb
125 N/Wb
0.2 N/Wb
The emf produced in a wire by its motion across a magnetic field does not depend upon the
Diameter of the wire
Length of the wire
Orientation of the wire
Flux density of the field
The ratio of the total flux (flux in iron path) to the useful flux (flux in air gap)
Leakage flux
Leakage current
Leakage coefficient
Leakage factor
What is the SI unit of conductance?
Siemens
Mhos
Ohms
1/Ohms
Calculate the permeability (in T/A. t/m) of a magnetic material that has a relative permeability of 300
3.78 x 10^4
3.78 x 10^-5
3.78 x 10^-3
3.78 x 10^-6
The energy stored in an electrostatic field or electromagnetic field is called
Electromagnetic energy
Kinetic energy
Potential energy
R est energy
Flux density is measured in
Tesia
Weber
Ampere- turn
Maxwell
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
What is the unit of reluctance?
Maxwell
Gauss
At/Wb
Weber
The core of a transformer heats up when its primary is fed from an ac source because of
permeability
ferromagnetism
reluctance of core
hysteresis loss
Permeability means
The conductivity of the material for magnetic lines of force
The magnetization test in the material after exciting field has been removed
The strength of an electromagnet
The strength of the permanent magnet
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
If two similar charges 1 coulomb each are placed 1 m apart in aira then the force of repulsion is
8 × 10^6 N
9 × 10 ^9 N
10^6 N
5 × 10^6 N
Magnetic fields do not interact with
Moving permanent magnets
Stationary permanent magnets
Moving electric charges
Stationary electric charges
What is the usual value of leakage coefficient for electrical machines?
0.5 to 1
1 to 5
5 to 10
1.15 to 1.25
The phenomenon that when an electric current passes through an anisotropic crystala there is an absorption or liberation of heat due to the non-uniformity in current distribution.
Bridgman effect
Corona effect
Dember effect
Destriau effect
The emf induced in a coil due to the changing current of another neighboring coil is called
Mutually induced emf
Self induced emf
Statically induced emf
Dynamically induced emf
Refers to the magnetic lines
Flux
Hysteresis
Current
Magnetomotive force
What is the diameter of an atom?
About 10^-10 m
About 10^-10 cm
About 10^-10 mm
About 10^-10 �m
Flux linkages equals
Flux times area of core
Flux times number of turns times area of core
Flux times number of turns times length of core
Flux times number of turns
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
If the number of valence electrons of an atom is exactly 4a then the substance is called
a semiconductor
a conductor
an insulator
a cryogenic conductor
If the value of 25 of a conductor is 1/230 per oCa then the value of 0is
1/180 peroC
1/150 per oC
1/280 per oC
1/230 per oC