It is a convenient way of representing the energy of different orbits. The first orbit represents the first energy level; the second orbit represents the second energy level and so on. The larger orbit of an electron the greater is its energy ad higher in energy level.
Ø An atom
consists of a positively charged nucleus around which negatively charged
electrons revolve in different circular orbits.
Ø The
electrons in each permitted orbit have a certain fixed amount of energy. The
larger orbit, the greater is the energy of electrons.
Ø If an
electron is given additional energy (heat, light etc), it is lifted to the
higher orbit. this state does not last long, because the electron soon falls
back to the original lower orbit.
The electros in the outermost orbit of an atom are known as valence electrons.
When the number of valence electron of an atom is less than
4, the material is usually a metal and
a conductor.
e.g. - sodium (2, 8,1), aluminum (2,8,3) etc.
When the number of valence electron of an atom is more than
4, the material is usually a non-metal
and an insulator.
e.g. – Nitrogen (2,5), Sulphur (2,8,6) etc.
When the number of valence electron of an atom is 4, the
material has both metal and non-metal properties, and is usually a semi-conductor.
e.g. – Silicon (2,8,4) and germanium (2,8,18,4)
Note- The outermost orbit can have a maximum of 8 electrons.
The atoms are consists small tiny negatively charges particles having negligible mass is known as electrons.
features of an electron is-
(i). charge on an electron, e = 1.602 x 10-19 coulomb
(ii). mass of an electron, m= 9.0 x 10-31 kg
(iii). radius of an electron, r = 1.9 x 10-15 m
Energy of an electron:-
An electron moving around the nucleus of an atom consist two energies. one is the kinetic energy(K.E) due to its motion and another one is potential energy(P.E) due to the charge on the nucleus.
i.e. total energy of an electron = K.E + P.E
The energy of an electron increases as its distances from the nucleus increases. that means electrons in the last orbit possess very high energy as compared to the electrons in the inner orbits.
These are mainly two types -
(i). Passive Components- The electronic components which are not capable of amplifying or processing an electrical signals are called passive components.
In other words a passive components is an electrical component that does not generate power but instead dissipates, stores or releases it.
example- Resistors, Capacitors and Inductors
(ii). Active Components:- The electronic components which are capable of amplifying or processing an electrical signals are called active components. Its also capable of supplying power.
example- Vacuum tubes, gas tubes and semiconductors
The word electronics is derived from electron which is present in all materials.
The branch of science and engineering that deals with the flow of electronics through vacuum or gas or semiconductor is known as electronics. that means the branch which essentially deals with electronics devices and their utilization.
Its are widely used in-
(i). In Communications
(ii). In Industrial
(iii). In Medical sciences and many more
Note- electronics deals in the micro and milli range of voltage, current and power but it can controls kilo and mega volts, amperes and watts.
The branch of science and engineering which deals with the generation of electrical power, transmission, distribution and proper utilisation of electrical energy for mankind and nation is known as electrical engineering.
It is a convenient way of representing the energy of different orbits. The first orbit represents the first energy level; the second orbit...
