Flux density is measured in
Tesia
Weber
Ampere- turn
Maxwell
Correct Answer :
A. Tesia
Related Questions
States that the ratio of the thermal conductivity is proportional to the absolute temperature for all metals.
Wien's displacement law
Hartleys law
Hall's law
Wiedemann Franz law
The temperature coefficient of resistance of semiconductors is
positive
zero
negative
infinite
The phenomenon by which a magnetic substance becomes a magnet when it is place near a magnet
Magnetic effect
Magnetic phenomenon
Magnetic induction
Electromagnetic induction
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 greater percentage of materials is _________.
diamagnetic
paramagnetic
ferromagnetic
non-magnetic
Electrons at the outer shell are called
Outer shell electrons
Inner shell electrons
Semiconductor electrons
Valence electrons
The electric potential at a point in air due to a charge is 21 V. If the air is replaced by a medium of relative permittivity of 3a then electric potential at that point will be
63 V
21 V
7 V
42 V
The branch of Engineering which deals with the magnetic effect of electric current is known as
Magnetism
Electromagnetism
Electrical engineering
Electronics engineering
______ is an electromagnet with its core in the form of a close magnetic ring.
S olenoid
Paraboloid
Toroid
Cycloid
A positively charged body has
deficit of electrons
excess of neutrons
excess of electrons
deficit of protons
Lenz' law states that the direction of the induced emf and hence current
Is determined by the rate of current flux
Is found by the right hand rule
Is found by the left hand rule
Always opposes the cause producing it
Which of the following is used by permanent magnets as the magnetic material?
iron
nickel
soft steel
hardened steel
When the relative permeability of a material is slightly less than 1a it is called _____ material.
diamagnetic
ferromagnetic
paramagnetic
non-magnetic
A commercial alloy of aluminum nickela and iron with cobalta copper and titanium added to produce about 12 grades.
Alnico
Brass
Aluminum
Constantan
The phenomenon by which a subtracts pieces of iron
Magnetism
Electromagnetism
Naturalism
Materialism
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
Which of the following has the least number of valence electrons?
Conductor
Semiconductor
Insulator
Semi- insulator
A test charge means a charge of
-1 C
1 electron
+1 C
-20 C
As the magnetic intensity decreasesa the relative permeability of a magnetic material
decreases
remains the same
increases
becomes zero
Which of the following is used by temporary magnets as the magnetic material?
Hardened steel
Cobalt steel
Soft iron
Tungsten steel
All matters (gasa liquid and solid) are composed of
Neutrons
Particles
Electrons
Atoms
Which of the following magnetic materials can be easily magnetized in both direction?
Soft magnetic materials
Hard magnetic materials
High hysteresis loss materials
Low hysteresis loss materials
If a 20 V potential is applied across a relay coil with 50 turns having 1 ? of resistancea the total magnetomotive producing magnetic flux in the circuit is
10 Wb
50 T
1000 A t/m
1000,t
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
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The core of a transformer heats up when its primary is fed from an ac source because of
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ferromagnetism
reluctance of core
hysteresis loss
Ohm's law cannot be applied to which material?
Copper
Silver
Silicon carbide
Aluminum
Referred to as the specific reluctance of a material
Resistivity
Reluctivity
Conductivity
Permeability
Refers to the non- metallic materials that have the ferromagnetic properties of iron.
Ferrites
Ferromagnetic
Diamagnetic
Paramagnetic
The permeability of permalloy is
Very much greater than permeability of air
Slightly greater than permeability of air
Slightly less than permeability of air
Equal to the permeability of air
The reluctance of a magnetic circuit is not dependent on which of the following?
Number of turns of coil
Magnetomotive force
Flux density in the circuit
Current in the coil