The reluctance of the magnetic circuit is ________ relative permeability of the material comprising the circuit.
directly proportional to
inversely proportional to
independent of
dependent of
Correct Answer :
B. inversely proportional to
Related Questions
The resistance of a material is ____________ its area of cross-section.
directly proportional
independent of
inversely proportional to
equal to
The total number of magnetic lines of force in a magnetic field is called
Magnetic flux
Magnetic flux density
Magnetic flux intensity
Magnetic potential
When the relative permeability of a material is much greater than 1a it is called _______ material.
diamagnetic
ferromagnetic
paramagnetic
non-magnetic
A length of wire has a resistance of 10 ohms. What is the resistance of a wire of the same material three times as long and twice the cross-sectional area?
30 ohms
20 ohms
15 ohms
7 ohms
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
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
Steel is hard to magnetize because of its
Low permeability
High permeability
High density
High retentivity
One coulomb of charge consists of ________ electrons.
624× 10^16
62.4 × 10^16
6.24 × 10^16
0.624 × 10^16
A law that states that the polarity of the induced voltage will oppose the change in magnetic flux causing the induction.
Joule's law
Faraday's law
Coulomb's law
Lenz' law
A magnetic pole produces 5000 field lines. How much is the flux in webers? A. 50 × 10^-6
5 × 10^-6
500 × 10^-6
500 × 10^-5
What is the unit of reluctance?
Maxwell
Gauss
At/Wb
Weber
The magnetic flux of 2000 lines is how many Maxwells?
Which of the following is used by temporary magnets as the magnetic material?
Hardened steel
Cobalt steel
Soft iron
Tungsten steel
When the relative permeability of a material is slightly more than 1a it is called ______ material.
diamagnetic
ferromagnetic
paramagnetic
non-magnetic
How many electrons are needed in the valence orbit to give a material's stability?
The magnetic field of a magnetized iron bar when strongly heated
Becomes weaker
Becomes stronger
Reverses in direction
is unchanged
The temperature coefficient of resistance of conductors is
positive
zero
negative
infinite
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
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
A good conductor has how many valence electrons?
Which of the following is a natural magnet?
Steel
Magnesia
Lodestone
S oft iron
The magnetic field of a bar magnet most closely resembles the magnetic field of
a horseshoe magnet
a straight current- carrying wire
a stream of electrons moving parallel to one another
a current- carrying wire loop
A permanent magnet does not exert a force on
an unmagnetized iron bar
a magnetized iron bar
a moving electric charge
a stationary electric charge
The amount of magnetizing force to counter balance the resid magnetic material is referred to as
Reluctivity
Susceptivity
Coercivity
Retentivity
Paramagnetic substance has a relative permeability of
Slightly less than one
Equal to one
Slightly equal to one
Very much greater than one
What is the measure of the density and sign of the electric charge at a point relative to that at some time?
Electric potential
Electric charge
Electric current
Electric intensity
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
Who discovered superconductivity in 1911?
Kamerlingh Onnes
Alex Muller
GeoryBednorz
Charles Coulomb
Cobalt is an example of a ______ material.
Paramagnetic
Diamagnetic
Ferromagnetic
Non- magnetic
Hysteresis refers to the ______ between flux density of the material and the magnetizing force applied.
Leading effect
Ratio
Equality
Lagging effect