The contribution to the ionization in an ionization chamber by electrons liberated from t he walls.
Skin effect
Walt effect
Hall effect
Edison effect
Correct Answer :
B. Walt effect
Related Questions
If the value of 0 a conductor is 1/234 per oCa then the value of 18is
1/218 per oC
1/252 peroC
1/272 per oC
1/273 per oC
A magnetic material losses its ferromagnetic properties at a point called
Curie temperature
Inferred absolute temperature
Room temperature
Absolute temperature
When the ferromagnetic substance is inserted in a current- carrying solenoida the magnetic field is
Greatly decreased
Greatly increased
Slightly decreased
Slightly increased
Materials that have very high permeabilities (hundreds and even thousands times of that of free space)
Paramagnetic
Non- magnetic
Ferromagnetic
Diamagnetic
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 space outside the magnet where its pole have a force of attraction or repulsion on a magnetic pole is called
Magnetic field
Electric field
Electromagnetic field
Free Space Field
The force between two magnetic poles is _____ the relative permeability of the medium.
directly proportional to
independent of
inversely proportional to
equal to
The force between two magnetic poles is _______ their pole strengths.
directly proportional to
the sum of
inversely proportional to
the product of
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
The magnetic potential in a magnetic circuit can be measured in terms of
Mmf
Emf
Farad
Coulomb
Which of the following electric quantities is vector in character?
Field
Charge
Energy
Potential Difference
This paper does not exhibit electricity because it contains the same number of
protons and electrons
neutrons and electrons
neutrons and positrons
atoms
A negatively charge body has
deficit of electrons
excess of protons
excess of electrons
deficit of neutrons
What determines the value of the temperature coefficient of resistance of a material?
length
cross-sectional area
volume
nature and temperature
What is the cgs unit of magnetomotive force?
Gilbert
Ampere- turn
Maxwell
Weber
The electric flux density is a ________ quantity.
phasor
vector
scalar
variable
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
Theory of ferromagnetic phenomena which assumes each atom is a permanent magnet which can turn freely about its center under the influence of applied field and other magnets.
Ewing's theory of ferromagnetism
Oersted's ferromagnetism theory
Maxwell's magnetic theory
Ampere's circuital law
The property of a material which opposes the creation of magnetic flux in it
Resistance
Reluctance
Permeance
Conductance
The tiniest element of matter
Atom
Proton
Electron
Neutron
What is the value of the absolute permittivity of air?
8.854 F/m
8.854 × 10^-12 mF/m
8.854× 10^-12 F/m
8.854 × 10^-12 F/m
Electron is a Greek word for
amber
Fire
Stone
Heat
The resistance of a material is ____________ its area of cross-section.
directly proportional
independent of
inversely proportional to
equal to
Electric potential is a _______ quantity.
scalar
phasor
vector
variable
What is another name for relative permittivity?
Dielectric strength
Electric intensity
Potential gradient
Dielectric constant
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
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
One ampere- turn is equivalent to _____ gilberts
A magnetic pole produces 5000 field lines. How much is the flux in webers? A. 50 × 10^-6
5 × 10^-6
500 × 10^-6
500 × 10^-5
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