A current if flowing east along a power line. If the earth's field is neglecteda the direction of the magnetic field below it is
North
South
East
West
Correct Answer :
A. North
Related Questions
When a wire loop is rotated in a magnetic field the direction of the induced emf changes one in every _______ revolution
Which of the following materials has permeability slightly less than that of free space?
Paramagnetic
Non- magnetic
Ferromagnetic
Diamagnetic
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
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
The induced emf in a wire loop that is moved parallel to a uniform magnetic field is
Zero
Dependent on the area of the loop
Dependent on the shape of the loop
Dependent on the magnitude of the field
Electronic current in a wire is the flow of ____________ electrons.
free
valence
bound
loose
The evaporation of electrons from a heated surface is called
Radiation
Convection
Thermionic emission
Conduction
Small voltages generated by a conductor with current in an external magnetic field.
Skin effect
Magnetic effect
Hall effect
Flywheel Effect
The force between two magnetic poles is _______ their pole strengths.
directly proportional to
the sum of
inversely proportional to
the product of
What is used as the insulating material or dielectric in an electric ion
Oiled paper
Mica
Paraffin
Tit anate compound
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
Magnetic intensity is a
Phasor quantity
Physical quantity
Scalar quantity
Vector quantity
A one cubic cm of copper has how many free electrons at room temperature?
80 × 10^18
8.5 × 10^22
20 × 10^10
50 × 10^20
The hot resistance of an incandescent lamp is about _______ its cold resistance.
10 times
100 times
5 times
50 times
The B-H curve of ________ is not a straight line.
air
wood
silicon steel
soft iron
Permeance is analogous to
Conductance
Reluctance
Admittance
Resistance
Temporary magnets are commonly employed in
electric instruments
motors
moving coils loudspeakers
magnetos
One coulomb of charge consists of ________ electrons.
624× 10^16
62.4 × 10^16
6.24 × 10^16
0.624 × 10^16
The reluctance of a magnetic circuit varies with
length × area
area � length
length � area
length + area
The quantity of magnetism retained by a magnetic material after withdrawal of the magnetizing force is called
Leftover magnetism
Hysteresis
Residual magnetism
Coercivity
What is the diameter of an atom?
About 10^-10 m
About 10^-10 cm
About 10^-10 mm
About 10^-10 �m
The magnetic materials should have a large hysteresis loss for one of the following applications.
Transformers
ACmotors
Permanent Magnets
DC generators
When a current carrying conductor is placed in a magnetic fielda the maximum force will act on the conductor when the conductor is at an angle of _______ to the magnetic field.
45o
60o
30o
90o
This paper does not exhibit electricity because it contains the same number of
protons and electrons
neutrons and electrons
neutrons and positrons
atoms
What principle states that each electron in an atom must have a different set of quantum numbers?
Inclusion principle
Exclusion principle
Quantum principle
Electron principle
It is the reciprocal of reluctance and implies the case of readiness with which magnetic flux is developed.
R esistance
Conductance
Permeance
I nductance
The physical motion resulting from the forces of magnetic fields is called
Motor action
Rotation
Repulsion
Torque action
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
A law relating between the magnetic and electric susceptibilities and the absolute temperatures which is followed b ferromagnetsa antiferromagnetsa non-polar ferroelectricsa antiferroelectrics and some paramagnets.
Curie's Law
Child's Law
CR Law
Curie-Weiss Law
The phenomenon by which a subtracts pieces of iron
Magnetism
Electromagnetism
Naturalism
Materialism