What is used as the insulating material or dielectric in an electric ion
Oiled paper
Mica
Paraffin
Tit anate compound
Correct Answer :
B. Mica
Related Questions
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
If the number of valence electrons of an atom is more than 4a the substance is called
a semiconductor
a conductor
an insulator
a semi-insulator
______ is an electromagnet with its core in the form of a close magnetic ring.
S olenoid
Paraboloid
Toroid
Cycloid
The electric flux density is a ________ quantity.
phasor
vector
scalar
variable
Electric potential is a _______ quantity.
scalar
phasor
vector
variable
Calculate the flux density that will be produced by the field intensity of 2000 a. t/m for a permeability of 126 x 10^-6 T/A.t/m
0.252 G
0.252 x 10^-2 T
0.252 T
0.252 x 10^-2 G
Defined as the flux density produced in it due to its own induced magnetism
Magnetic field intensity
Electric field intensity
Electromagnetic field intensity
Intensity magnetization
This paper does not exhibit electricity because it contains the same number of
protons and electrons
neutrons and electrons
neutrons and positrons
atoms
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 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
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 magnetic potential in a magnetic circuit can be measured in terms of
Mmf
Emf
Farad
Coulomb
The temperature coefficient of resistance of semiconductors is
positive
zero
negative
infinite
The temperature coefficient of resistance of eureka is
p ositive
negative
almost zero
i nfinite
The resistance of a material is ____________ its area of cross-section.
directly proportional
independent of
inversely proportional to
equal to
The phenomenon by which a subtracts pieces of iron
Magnetism
Electromagnetism
Naturalism
Materialism
The magnetic flux through a coil changes. This results to the induced emf acting in a direction as to
Oppose the change
Aid the change
Either oppose or aid the change
Neither oppose nor aid the change
A magnetic circuit carries a flux iin the iron part and a fluxgin the air gap. What is the leakage coefficient?
i/g
i × g
g/ i
i + g
Ohm's law can be used only to a _____ circuit or component.
Unilateral
Exponential
Trivalent
Linear
A good conductor has how many valence electrons?
When the relative permeability of a material is much greater than 1a it is called _______ material.
diamagnetic
ferromagnetic
paramagnetic
non-magnetic
The quantity 10^6 maxwells is equivalent to one
Weber
Gauss
Gilbert
Tesla
In electro-mechanical conversion devices like generators and motors the reason why a small air gap is left between the rotor and stator is to
permit mechanical clearance
increase flux density in air gap
decrease the reluctance of magnetic path
complete the magnetic path
The force which set ups or tends to set up magnetic flux in a magnetic circuit
Dynamic force
Electromotive force
Potential difference
Magnetomotive force
The emf induced in a coil due to the change of its own flux linked with it is called
Mutually induced emf
Dynamically induced emf
Statically induced emf
Self induced emf
The temperature coefficient of resistance of a conductor ______ with an increase in temperature.
increases
decreases
remains the same
becomes negative
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 property of a material which opposes the creation of magnetic flux in it
Resistance
Reluctance
Permeance
Conductance
The physical motion resulting from the forces of magnetic fields is called
Motor action
Rotation
Repulsion
Torque action
Who demonstrated that there are magnetic effects around every current-carrying conductor and that current-carrying conductors can attract and repel each other just like magnets?
Luigi Galvani
Hans Christian Oersted
Charles Coulomb
Andre Ampere