Another term for corona discharge.
Lightning
Sparking
Aurora
Corona Effect
Correct Answer :
C. Aurora
Related Questions
If the right handed bottle-opener cork screw is assumed to be along the conductor so as to advance in the direction of current flow, the motion of its handle will indicate the direction of magnetic flux produced around the conductor. This is known as
Right hand rule
Left hand rule
Cork screw rule
End rule
If a magnetic flux cuts across 200 turns at a rate of 2Wb/sa the induced voltage according to Faraday's law is about
400 V
100 V
200 V
600 V
The amount of magnetizing force to counter balance the resid magnetic material is referred to as
Reluctivity
Susceptivity
Coercivity
Retentivity
The process by which an emf and hence current is generated or induced in a conductor when there is a change in the magnetic flux linking the conductor is called
Electromagnetic induction
Mutual induction
Faraday's law
Electromagnetic interference
Amorphous solid is also called
Crystalline
Non- crystalline
Polycrystalline
Homogenous
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
A 6- V battery is connected across a solenoid of 100 turns having a resistance of 2 ?a Calculate the number of ampere turns?
A magnetic field is
The current flow through space around a permanent magnet
The force set up when current flows through a conductor
The force that drives current through a resistor
The force between the plates of a charged capacitor
Under ordinary conditionsa a body is considered
positively charged
neutral
negatively charged
stable
If the number of valence electrons of an atom is less than 4a then the substance is probably
a metal
an insulator
a non-metal
a semiconductor
Referred to as the specific reluctance of a material
Resistivity
Reluctivity
Conductivity
Permeability
What bond is formed when one or more electrons in the outermost energy orbit of an atom are transferred to another?
Ionic
Covalent
Metallic
Van der Waals
The magnetic field around the conductor is determined by the
Size of the conductor
Amount of current
Current divided by the resistance
Resistance divided by the current
The electric field intensity between the parallel plate air capacitor is 20 N/C. If an insulating slab of relative permittivity 5 is placed between the platesa then electric field intensity will be
20 N/C
100 N/C
4N/C
40 N/C
What is the SI unit of conductance?
Siemens
Mhos
Ohms
1/Ohms
A t/m is a unit of
Mmf
Emf
Reluctance
Magnetizing force
When the relative permeability of a material is slightly more than 1a it is called ______ material.
diamagnetic
ferromagnetic
paramagnetic
non-magnetic
Ohm's law cannot be applied to which material?
Copper
Silver
Silicon carbide
Aluminum
An effect which is generally used in the gausameter to measure flux density.
Skin effect
Magnetic effect
Hall effect
Flywheel effect
Refers to the magnetic lines
Flux
Hysteresis
Current
Magnetomotive force
At/m is a unit of
mmf
magnetic force
reluctance
magnetic flux density
The magnetic field of a magnetized iron bar when strongly heated
Becomes weaker
Becomes stronger
Reverses in direction
is unchanged
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
A germanium atom has an atomic weight of72. How many neutrons are there?
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
If the value of 25 a conductor is 1/255 per oCa then the value of 20is
1/300 per oC
1/250 peroC
1/230 per oC
1/260 per oC
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
If the length and area of cross-section of a wire are doubleda then its resistance
becomes four times
becomes sixteen times
remains the same
becomes two times
Hysteresis is a phenomenon of _________ in a magnetic circuit.
setting up constant flux
lagging of H behind B
lagging B behind H
leading B ahead H
What is another name for relative permittivity?
Dielectric strength
Electric intensity
Potential gradient
Dielectric constant