An electron- volt (eV) is a unit of
Energy
Potential difference
Charge
Momentum
Correct Answer :
A. Energy
Related Questions
The property of magnetic materials of retaining magnetism after withdrawal of the magnetizing force is known as
Retentivity
Reluctivity
Resistivity
Conductivity
A magnetic material losses its ferromagnetic properties at a point called
Curie temperature
Inferred absolute temperature
Room temperature
Absolute temperature
The magnetic flux through a wire loop in a magnetic field does not d
T he area of the loop
The magnitude of the field
The shape of the loop
The angle between the plane of the loop and the direction
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
How many neutrons does a copper atom have?
Permanent magnets can be found in
electric bells
earphones
relays
dy namic loudspeakers
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
When the relative permeability of a material is slightly more than 1a it is called ______ material.
diamagnetic
ferromagnetic
paramagnetic
non-magnetic
One farad equals
1 coulomb/volt
1 newton/coulomb
1 newton-meter
1 volt/second/ampere
A length of wire has a resistance of 10 ohms. What is the resistance of a wire of the same material three times as long and twice the cross-sectional area?
30 ohms
20 ohms
15 ohms
7 ohms
If the solenoid is gripped by the right hand with the fingers pointing the direction of current flowa the outstretched thumb will then point the north pole. This is known as
Right hand rule
Helix rule
End rule
Cork screw rule
What determines the value of the temperature coefficient of resistance of a material?
length
cross-sectional area
volume
nature and temperature
If the resistance of a material 2 m long and 2 m^2 in area of cross-section is 1.6 ×10^-8 ?a then its resistivity is
3.2 × 10^-8 ?-m
1.6 × 10^-8 ?-m
0.64 × 10^-8 ?-m
0.16 × 10^-8 ?-m
A law establishing the fact that the algebraic su of the rises and drops of the mmf around a closed loop of a magnetic circuit is equal to zero.
Kirchhoff's circuital law
Maxwell's circuital law
Ampere's circuital law
Coulomb's circuital law
Formed when there exist distant electronic interactions between (opposite) charges present in the neighboring atoms or molecules.
Ionic bond
Covalent bond
Metallic bond
Van der Waals bond
Hydrogen is an example of a _____ material.
Paramagnetic
Diamagnetic
Ferromagnetic
N on- magnetic
The temperature coefficient of resistance of a conductor ______ with an increase in temperature.
increases
decreases
remains the same
becomes negative
If you hold the conductor with right hand so that the stretched thumb points in the direction of the currenta then encircling fingers will give the direction of magnetic lines of force round the conductor. This is known as
Left hand cork screw rule
Right hand cork screw rule
Left hand rule
Right hand rule
Defined as the ratio of the volume occupied by the atoms or ions in a unit cell divided by the volume of the unit cell and is used to measure the compactness of a crystal.
Atomic packing factor (APF)
Ionic Packing Ratio (IPR)
Atomic compacting factor (ACF)
Ionic compacting ratio (ICR)
The flux density in an air-cored coil is 10^-3 Wb/m^2. With a cast iron core of relative permeability 100 inserteda the flux density will become
10^-3 Wb/m^2
10^-2 Wb/m^2
10^3 Wb/m^2
0.1 Wb/m^2
What is used as the insulating material or dielectric in an electric ion
Oiled paper
Mica
Paraffin
Tit anate compound
What is the SI unit of conductivity?
Ohms/m
Ohms-m
Siemens-m
Siemens/m
The lagging effect between flux density of the material and the magne
Permeance
Eddy current
Hysteresis
R eluctance
A test charge means a charge of
-1 C
1 electron
+1 C
-20 C
The emission of electrons from hot bodies is called
Radiation effect
Edison effect
Skin effect
Half effect
The force of attraction or repulsion between two magnetic poles is directly proportional to their strengths.
Newton's first law
Faraday's first law of electromagnetic induction
Coulomb's first law
Coulomb's second law
An electron- volt (eV) is a unit of
Energy
Potential difference
Charge
Momentum
A negative ion results when an atom gains an additional
Electron
Proton
Neutron
Atom
Hysteresis loss can be reduced by one of the following.
Increasing mmf of the circuit
Using material narrow hysteresis loop
Using ferromagnetic core
Laminating the magnetic circuit
Which of the following statements is TRUE?
Silicon dioxide is a good
The current carriers in conductors are valence electrons
For conductorsa the valence electron are strongly attracted to the nucleus
The valence electrons are located in the nucleus of an atom