The emission of electrons from hot bodies is called
Radiation effect
Edison effect
Skin effect
Half effect
Correct Answer :
B. Edison effect
Related Questions
Electric field intensity at a point due to a given charge ______ if the relative permittivity of the medium decreases.
decreases
remains unchanged
increases
b ecomes zero
Materials whose permeabilities are slightly greater than that of free space
Paramagnetic
Non- magnetic
Ferromagnetic
Diamagnetic
Three charges of +5 Ca -6 C and +9 C are placed inside a sphere. What is the total flux passing through the surface of sphere?
8 C
14 C
20 C
-6 C
Temporary magnets are commonly employed in
electric instruments
motors
moving coils loudspeakers
magnetos
Back emf refers to the
Current equal to the applied emf
Opposing emf
Current opposing the applied emf
Voltage opposing the applied emf
What is the SI unit of reluctance?
At
At/m
N/Wb
At/Wb
Electric field intensity is measured in
volts/meter
Newton/meter
Newton-meter
Amperes/meter
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
The resistance of a material is ____________ its area of cross-section.
directly proportional
independent of
inversely proportional to
equal to
A principle that states that only two electrons with different spins are allowed to exist in a given orbit
Bohr's principle
Pauli exclusion principle
Avogadro's principle
Coulomb's principle
The electric potential across part AB of a circuit is 5 V; point A being at higher potential. If a charge of 5 Cmoves from A to Ba then energy released as
5 joules
25 joules
10 joules
100 joules
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
Bonding of atoms that is due to the force of attraction between positive ions and a group of negative ions
Ionic bond
Covalent Bond
Electrostatic Bond
Metallic bond
If the relative permittivity of a material is 10a then its permittivity is
4 × 10^7F/m
4 × 10^-6 F/m
8.854× 10^-11 F/m
8.854 × 10^-12 F/m
The electrons in the last orbit of an atom are called _______ electrons.
free
valence
bound
thermionic
The contribution to the ionization in an ionization chamber by electrons liberated from t he walls.
Skin effect
Walt effect
Hall effect
Edison effect
One farad equals
1 coulomb/volt
1 newton/coulomb
1 newton-meter
1 volt/second/ampere
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
The science of adapting electronics to aerospace flight.
Avionics
Aerotronics
Aerodynamics
Astrionics
What is the maximum number of electrons that can be accommodated in the last orbit of an atom?
How many turns are needed to produce a magnetomotive force of 1000 A.t for a coil with 6 amperes?
6000 turns
600 turns
167 turns
67turns
Why is it that the magnitude of magnetomotive force required for air gap is much greater than that required for iron part of a magnetic circuit?
Because air is a gas
Because air has the highest relative permeability
Because air is a conductor of magnetic flux
Because air has the lowest relative permeability
Who demonstrated the theory of electromagnetic induction in 1831?
Michael Faraday
Andre Ampere
James Clerk Maxwell
Charles Coulomb
Flux density is measured in
Tesia
Weber
Ampere- turn
Maxwell
Ohm's law cannot be applied to which material?
Copper
Silver
Silicon carbide
Aluminum
Electromotive force in a circuit
causes free electrons to flow
increases the circuit resistance
maintains circuit resistance
is needed to make the circuit complete
The branch of Engineering which deals with the magnetic effect of electric current is known as
Magnetism
Electromagnetism
Electrical engineering
Electronics engineering
A positively charged body has
deficit of electrons
excess of neutrons
excess of electrons
deficit of protons
The diameter of a hydrogen atom is approximately ______ cm.
1.1 x 10^-6
1.1 x 10^7
1.1 x 10^-8
1.1 x 10^-9
The mass of proton is __________ the mass of an electron.
equal to
about 1837 times
less than
200 tim es