If two similar charges 1 coulomb each are placed 1 m apart in aira then the force of repulsion is
8 × 10^6 N
9 × 10 ^9 N
10^6 N
5 × 10^6 N
Correct Answer :
B. 9 × 10 ^9 N
Related Questions
Hipernik is an alloy containing __________ iron and __________ nickel.
40% ; 60%
60% ; 40%
50% ; 50%
70% ; 30%
What determines the atomic number of an element?
The number of protons
The number of electrons
The number of neutrons
The number of neutrons and protons
What is another name for relative permittivity?
Dielectric strength
Electric intensity
Potential gradient
Dielectric constant
Refers to the non- metallic materials that have the ferromagnetic properties of iron.
Ferrites
Ferromagnetic
Diamagnetic
Paramagnetic
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)
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
A law that states that the polarity of the induced voltage will oppose the change in magnetic flux causing the induction.
Joule's law
Faraday's law
Coulomb's law
Lenz' law
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
One weber of flux is equal to _______ magnetic lines of force.
10^6
10^10
4 × 10^7
10^8
__________ is a substance of whose molecules consist of the same kind of atom.
Mixture
Compound
Element
Isotope
Electron is a Greek word for
amber
Fire
Stone
Heat
When the relative permeability of a material is much greater than 1a it is called _______ material.
diamagnetic
ferromagnetic
paramagnetic
non-magnetic
Who discovereda the relationship between magnetism and electricity that serves as the foundation for the theory of electromagnetism?
Luigi Galvani
Hans Christian Oersted
Andre Ampere
Charles Coulomb
What is the measure of the density and sign of the electric charge at a point relative to that at some time?
Electric potential
Electric charge
Electric current
Electric intensity
The temperature coefficient of resistance of conductors is
positive
zero
negative
infinite
A germanium atom has an atomic weight of72. How many neutrons are there?
The permittivity of a material is given by one of the following formulas.
DE
E/D
D^2/E
D/E
The relation between absolute permittivity of air ( 0)a absolute p and velocity of light (c) is given by
0 0= c^2
0 0= c
1/ 0 0= c
1/ 0 0= c^2
Materials that have very high permeabilities (hundreds and even thousands times of that of free space)
Paramagnetic
Non- magnetic
Ferromagnetic
Diamagnetic
The electric field intensity between the parallel plate air capacitor is 20 N/C. If an insulating slab of relative permittivity 5 is placed between the platesa then electric field intensity will be
20 N/C
100 N/C
4N/C
40 N/C
One coulomb of charge consists of ________ electrons.
624× 10^16
62.4 × 10^16
6.24 × 10^16
0.624 × 10^16
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
The phenomenon by which a subtracts pieces of iron
Magnetism
Electromagnetism
Naturalism
Materialism
The hot resistance of an incandescent lamp is about _______ its cold resistance.
10 times
100 times
5 times
50 times
Which of the following magnetic materials can be easily magnetized in both direction?
Soft magnetic materials
Hard magnetic materials
High hysteresis loss materials
Low hysteresis loss materials
Permeability means
The conductivity of the material for magnetic lines of force
The magnetization test in the material after exciting field has been removed
The strength of an electromagnet
The strength of the permanent magnet
Which of the following has the least number of valence electrons?
Conductor
Semiconductor
Insulator
Semi- insulator
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
At/m is a unit of
mmf
magnetic force
reluctance
magnetic flux density
The magnetic flux of 2000 lines is how many Maxwells?