MAGNETIC EFFECTS OF ELECTRIC CURRENT SOURCES OF ENERGY.pdf

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MAGNETIC EFFECTS OF ELECTRIC CURRENT SOURCES OF ENERGY.pdf

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MAGNETI
C EFFECTS OF ELECTRIC CURRENT

SOURCE
S

OF ENERGY




IMPORTANT FACTS
:



A source of energy provides energy in a convenient form over a long period of time.



Sources of energy can be classified as renewable and non
-
renewable sources.



Solar energy is the main source of ener
gy on the earth.



Solar cookers, solar water heaters and solar concentrators are some devices used for
harnessing solar energy.



Solar cells are devices that convert solar energy directly into electricity.



Solar energy also manifests itself in nature a
s the energy of winds, water flowing
through rivers, ocean waves, besides oc
e
an thermal energy.



Energy harnessed through wind energy devices is utilized either to do mechanical
work, or to produce electricity.



Energy derived from the hot spots beneath
the earth is called geothermal energy.



Green plants convert solar energy into chemical energy through the process of
photosynthesis. This energy is known as bio
-
energy.



Biomass is utilized to produce heat by burning it or to produce biogas through its
anaerobic decomposition in a biogas plant.



Hydrogen and alcohol could be a source of energy in future.



Fossil fuels like coal, petroleum and natural gas are a mixture of hydrocarbons. These
are fossil remains produced by the decay of plants and marine
animals that were
buried in the earth millions of years ago.



Fuels like coal, petroleum and natural gas are being utilized at very high rates, resulting
in fast depletion of their known reserves. Fossil fuels may not be available in future, as
these are
not being formed now.



Fuels are characterized by their calorific value and ignition temperature, besides the
nature of product produced by their combustion.



The three conditions essential for combustion are attainment of ignition temperature,
presenc
e of oxygen and a combustible material.



The factors that help to choose a good fuel for a given purpose are its availability, cost,
its characteristic and physical properties, besides considerations of the effects of its
by
-
products on environment.


TYPE
S OF ENERGY


1.

Wind Energy:

The energy possessed due to moving air is called wind energy.


Advantages:


(i)

It does not cause any pollution.

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(ii)

The source of wind energy is air. (Renewable Energy)


(iii)

It is available free of cost.

2.

Water Energy:
T
he energy possessed due to flowing of water is called the water
energy.


Water Wheel:

The device used for obtaining energy from flowing water is called water
wheel. The basic principle of water wheel is that the moving water rotates the water wheel and
thi
s water wheel can be made to turn machines, which do work for us.

3.

Electric Power Plants:

The set
-
up, which can produce large quantity of electricity,
from a few kilowatts to a few hundred megawatts, are called power plants. There are three
types of powe
r stations (plants). These are:


(a)

Hydroelectric power stations;


(b)

Thermal power stations;


(c)

Nuclear (or atomic power stations)


Principle of hydroelectric power:

The potential energy of the water stored at great
heights in the dams is converted in
to kinetic energy by flowing water to flow at high speeds
due to which electricity is generated. The electric power so generated is called hydroelectric
power.

4.

Solar Energy:

The energy obtained from the sun is called solar energy.


Advantages of Solar E
nergy


(i)

It is inexhaustible source of energy.


(ii)

I
t does not cause pollution.


(iii)

It is available free of cost.


Disadvantages of Solar Energy:


(i)

It is not available all the time.


(ii)

It is very much diffused and scattered.

5.

Tidal Energy:

The energy obtained from tides is called tidal Energy.


Merits of tidal energy




It is an inexhaustible source of energy.




It is independent of uncertainty of rainfall.




It is a pollution free source of energy.




It does not require large area of val
uable land.


Demerits of tidal energy




Power generation is intermittent due to variation in tidal range.




The most difficult problem in the use of tidal power are the barrage construction in
areas of high tidal flow and corrosion of barrage.

6.

Merits
of wave energy





It is a renewable and pollution free source of energy.




It does not require large land areas.


Demerits of wave energy




The power supply is variable in nature due to variability in wave formation.

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It is expensive.




Marine life c
ould be affected due to wave energy harnessing structures.

7.

Merits of OTEC




The electric power produced is continuous, renewable and pollution free.




OTEC system enriches the fishing grounds by transferring nutrients from the
unproductive deep waters

to the warmer surface.




OTEC system does not have daily or seasonal variations in their output as in case
with the solar energy devices.


Demerits of OTEC




OTEC system requires a lot of capital investment.




The conversion efficiency is low as there
is small temperature difference between
the surface water and the deep water.

8.

Merits of geothermal energy




It is the most versatile and least polluting renewable source of energy.




It is relatively inexpensive and power generation level is higher a
s compared to
solar energy and wind energy.


Demerits of geothermal energy




Though geothermal energy is inexhaustible, a single bore has a limited life span of
about 10 years.




Geothermal hot spots are scattered.




Noise pollution is caused by drillin
g operations at geothermal sites.

9.

Advantages of nuclear fusion over nuclear fission


Energy released in fusion reaction is much greater than energy released in fission
reaction. The products of fusion are not radioactive whereas it is radioactive in cas
e of nuclear
fission and require careful disposal.


Hazards of nuclear power generation and safety measures


The major hazards of nuclear power generation are:




Storage and disposal of spent or used nuclear fuels as they continue to decay into
harmful
subatomic particles (radiations). This would lead to environmental
contamination.




There is a risk of accidental leakage of nuclear radiation.




It has high cost of installation of a nuclear power plant.


Types of Nuclear Reaction
s
:


(i)

Nuclear Fusion
Reaction:

The process in which two or more nuclei of lighter
atoms combine to form a heavy nucleus with the liberation of a large amount of energy is
called fusion reaction. For example:


MeV)

(17.3

Energy.

Tremendous
He
H
H
4
2
2
1
2
1
+

+


(ii)

Nuclear Fission Reactions:

The process

of splitting of a nucleus of a heavy atom
into a number of nuclei of smaller mass with the liberation of large amount of energy is called
nuclear fission. For example

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MeV)
(200
Energy
n
3
Kr
Ba
n
U
1
0
94
36
139
56
1
0
235
92
+
+
+

+


Cause of tremendous Amount of Energy:

The cause of tremendous
amount of
energy during the nuclear fission is the loss of mass. The loss of mass is also called mass
defect.


Einstein Equation:
2
mc
E
=


Where m = The mass lost or mass defect. c = the velocity of light. E = amount of
energy.


Chain React
ion:

A reaction in which the number of neutrons goes on increasing during
fission till whole of the fissionable material is disintegrated.


Nuclear Reactor:

It is a device, which is used for carrying out fission reaction at a
controlled rate. It is used to

generate electricity.


Nuclear fuel:

The fissionable material used in the nuclear reactor is called nuclear
fuel.



For ex., U
235
, Pu
239
.




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