Source Of Energy

The basic characteristics of a good source of energy are as follows:

1. The source of energy should not cause any kind of environmental pollution.

2. The source of energy should produce a great amount of energy per unit mass or volume.

3. It should not cause any kind of harm to people and should not be risky to the health of people handling it.

4. The source of energy should be easily available and should have the capacity to generate energy for maximum amount of time.

Non-renewable sources of energy refer to that class of sources of energy which are dependent on materials which are limited in quantity and has the possibility of getting completely depleted in the future if used in very rapid rate. For example, petroleum or coal is available through the deposit which is formed over thousands of years back and thus is limited in quantity to the generation of coal or petroleum takes thousands to millions of years.

Non-renewable sources or conventional sources of energy refer to that class of sources of energy which are dependent on materials which are limited in quantity and has the possibility of getting completely depleted in the future if used in very rapid rate. For example, petroleum or coal is available through the deposit which is formed over thousands of years back and thus is limited in quantity to the generation of coal or petroleum takes thousands to millions of years.

Conventional sources of energy cause environmental pollution as emit carbon dioxide and other pollutants on combustion.

The main reasons to avoid the use of fossil fuels as sources of energy:

1. Fossil Fuels cause heavy environmental pollution on being combusted as they emit carbon dioxide and other pollutants in the air.

2. Fossil fuels are limited or finite in quantity and hence their use should be limited to save it for future.

The basic characteristics of a good source of energy are as follows:

1. The source of energy should be sustainable and renewable.

2. It should not cause any kind of environmental pollution.

3. It should produce a great amount of energy per unit mass or volume.

4. It should not cause any kind of harm to people and should not be risky to the health of people handling it.

5. The source of energy should be easily available and should have the capacity

6. Energy and Good Fuel

According to the pie chart, coal is the fossil fuel which is widely used in India for energy production.

The main reasons to avoid the use of fossil fuels as sources of energy:

1. Fossil Fuels cause heavy environmental pollution on being combusted as they emit carbon dioxide and other pollutants in air.

2. Fossil fuels are limited or finite in quantity and hence their use should be limited to save it for future.

3. Incomplete combustion of fossil fuels causes liberation of carbon monoxide which is highly injurious to health.

The negative impacts of hydro power plant on ecosystem are as follows:

1. Since dams always have a reservoir where the abundant quantity of water is stored, the blocking of flowing water causes harm to aquatic animals and their migration.

2. Dams also causes submerging of the nearby lands and all the natural areas, agricultural lands and hence requires relocating of the people who lived previously near the dam area.

3. Water from the reservoirs of the dams is lost due to evaporation at a faster rate as compared to flowing water.

4. Normally reservoir water has a lesser amount of dissolved oxygen and is cooler as compared to normal water. So when such water is released, it causes negative impacts on the organisms and plants downstream.

The popular biomass used in India are as follows:

1. Cow Dung

2. Residues left after harvesting of crops.

3. Agricultural Waste

4. Sewage

5. Vegetable Waste

6. Wood

The typical composition of biogas is as follows:

Methane lies in the range of 50-75%

Carbon Dioxide lies in the range of 25-50%

Nitrogen lies in the range of 0-10%

Hydrogen lies in the range of 0-1%

Bio gas is the gas formed in the biogas plant due anaerobic oxidation of organic material. But the majority of the starting material for the biogas plant is the cow dung which is known as “gobar” in Hindi Language and hence the gas formed in the biogas plant is termed as the “gobar gas”

Biogas is an excellent fuel for cooking purposes and it also contains 75% of methane because of which biogas burns without giving any kind of smoke and also do not leave any residue after being heated.

Since biogas also uses waste water, it removes the oxygen demanding pathogens present in the waste thereby preventing the pollution of water bodies.

Biogas plants contain the residue after all the organic matter is converted to gas. This residue is rich in phosphorous and nitrogen which are the two main nutrients for plants. Hence this residue can be used as an organic fertilizer for plants.

The limitations of harnessing wind energy are as follows:

1. The setting up and maintenance of the wind farms is a costly affair.

2. Wind Mills and Wind Farms requires a large area of their setup.

3. Wind farms can be established only those areas where wind flows throughout the year and the speed of wind remains above 15km/hr.

The raw material required for the solar energy is sunlight which is freely available and sunlight is available as long as the sun exists and at the same time sunlight is inexhaustible. Hence solar energy is considered to be renewable source of energy.

All the solar cells available in the market are made from silicon, germanium [rarely]. Silicon is the only material in which the electrons flow when it exposed to sunlight.

Solar cooker box is used to cook food with help of sunlight. The sunlight when it shines on the solar cooker the food inside gets cooked due to the absorbed heat from sun rays.

To avoid the escaping of the heat from the solar cooker, the solar cooker is covered with glass as sunlight can pass through glass effectively but the heat inside the cooker will not be radiated out.

Solar Cell as the name suggests it has to deal with sun or more specifically sun’s energy or solar energy. Cell means any device which gives electricity.

So a solar cell will convert solar energy into electrical energy.

A single solar cell cannot generate large amount of electricity. So an array of connected solar cells constitute to form a solar panel which can give large amount of electricity.

The different forms of energy available in ocean are as follows:

1. Tidal Energy due to tides in oceans.

2. Wave Energy due to fast-moving ocean waves.

3. Ocean current energy due to ocean currents under the ocean.

4. Ocean thermal energy due to difference in water’s temperature at surface and deep inside the water.

Nuclear Fission as the name suggests nuclear which means relating to nucleus and fission means to break. So nuclear fission is a process in which a heavy nucleus breaks into smaller particles spontaneously or due to collision with a moving particle releasing a vast amount of energy.

Nuclear Fusion as the name suggests nuclear which means relating to nucleus and fusion means to join. So nuclear fission is a process in which two lighter nuclei come close enough to form one or more different atomic nuclei releasing a large amount of energy. The nuclear fusion reaction takes place at Sun where two hydrogen nuclei combine to form helium resulting in liberation of large amount of heat and light energy.

The disadvantages of nuclear power are as follows:

1. Nuclear power is mainly generated due to fission of a heavy nucleus and this reaction results in a chain reaction which can become uncontrollable.

2. Nuclear power generates large amount of radiation which is harmful to all living beings as this radiation can cause incurable diseases and genetic disorders.

3. Radioactive waste generated due to nuclear power plants cannot be disposed of easily.

Conventional sources of energy or Renewable Sources of Energy are those energy sources which will never be depleted as they are virtually unlimited in quantity.

In case of hydro power plant, flowing water causes the turbines to rotate and the water can be refilled due to rains and hence Hydro energy is considered to a renewable source of energy.

The two solar based devices which use solar energy are as follows:

1. Solar Cell

2. Solar Cooker

3. Solar Water Heater

The reason for the attainment of such high temperatures is that by the use of parabolic reflectors the rays of sunlight get concentrated at a particular point causing a greater elevation in temperature.

During the winding of the spring of a clock, the kinetic energy gets converted into stored potential energy of the spring.

A solar cell is a type of cell in which the electrons flow when sunlight is concentrated on it. Thus the flow of electron constitutes an electric current. So when we connect rechargeable batteries to solar cell, the batteries get charged due to the current flowing out of solar cell and hence in many applications solar cells are connected to rechargeable batteries.

The major energy production sources in the present world are due to fossil fuels and petroleum. Since the rise in energy demand, causes an extensive use of these resources and at the same time, the use of such resources causes heavy environmental pollution. Also, the extensive use of fossil fuels for energy production will cause the fossil fuel to deplete off completely in near future.

Fossil fuels are formed due to decaying of remains of plants, animals and organic matter over the period of thousands of years where the matter gets converted to solid form due to action of environmental agents like temperature pressure and heat.

The typical gases present in biogas are as follows:

1. Methane

2. Carbon Dioxide

3. Hydrogen

4. Hydrogen Sulphide

Biogas is more efficient as fuel as compared to fossil fuels in the following ways:

1. Biogas does not leave any ash and residue after combustion.

2. Biogas does not burn with a smoke and does not cause pollution.

India requires tidal energy on a larger scale as it is covered with water on all the three parts and on the other hand it requires the nuclear energy the least as it has less reserves of nuclear raw material.

Hydro power makes up 14.01 percent, with 44,189.43 MW of the total power generated in the country.

In case of hydro power plant, flowing water causes the turbines to rotate and the water can be refilled due to rains and hence Hydro energy is considered to renewable source of energy. Moreover, hydro energy does not release any kind of environmental pollutants.

Coke, on the other hand, belongs to the category of non-renewable sources of energy and also leads to the evolution of gaseous pollutants.

In older days the energy of the wind was used for sailing purposes on a large scale as the wind used to drive the boat or raft in the direction of wind.

Water was used in water wheels which were used to grind the wheat into flour and also the water steam used in steam engine.

Solar cooker is used to cook food with help of sunlight. The sunlight when it shines on the solar cooker the food inside gets cooked due to the absorbed heat from sun rays.

To avoid the escaping of the heat from the solar cooker, solar cooker is covered with glass as sunlight can pass through glass effectively but the heat inside the cooker will not be radiated out.

Hence the solar cooker covered by a plane glass slab will be more efficient as compared to the uncovered one.

People living in the hilly areas are exposed to the strong rays of the sun because of which they get sunburns. Sunburns are normally caused due to the ultraviolet rays present in the sunlight which has the intense heating effect causing the skin to get reddened.

This effect is not generally observed near the sea regions because the sun rays are not that strong near the sea surface in technical terms the intensity of sun rays is less at sea level.

Since the given source of energy is not sourced directly or indirectly from the sun, chances of solar energy are eliminated.

Since the energy is pollution free and at the same time technically difficult and also costly which implies that the energy is tidal energy.

Tidal energy is not available everywhere and also the initial cost for tidal energy is very high as compared to other forms of energy. Tidal energy is difficult to construct and it is also pollution free.

Any source of energy whether renewable or non-renewable source of energy contributes to environmental pollution directly or indirectly.

Let us take the example of hydro energy. Hydro energy does not emit any air pollutant but it harms environment in the following ways:

The negative impacts of hydro power plant on ecosystem are as follows:

1. Since dams always have a reservoir where abundant quantity of water is stored, the blocking of flowing water causes harm to aquatic animals and their migration.

2. Dams also cause submerging of the nearby lands and all the natural areas, agricultural lands and hence requires relocating of the people who lived previously near the dam area.

In case of wind energy the windmill blades are injurious to the birds.

During the nuclear fission process a heavy nucleus splits to form particles. As we know that the subatomic particles are held together by strong nuclear forces and when the particle breaks it releases a tremendous amount of energy. The energy released during the fission reaction is calculated by using the famous relation:

E = mc²

Where:

E = Energy released

m = mass defect = Total Mass before the reaction – Total mass after the reaction

c = speed of light

Given:

Solar Constant = 1.4 kW/m²

Solution:

Solar energy received at area of 1 m² = 1.4 kW/m²

So the energy received at an area of 5m² = 5 × 1.4

= 7 kW/m²

As in physics we know that electric current flow from higher potential to lower potential due to potential difference.

In a similar manner in nature there exists pressure difference between two locations or areas which causes the wind to flow.

A wind is air in motion and so the wind flows from area of high pressure to area of low pressure.

Wind energy is harnessed in following states of Tamil Nadu, Gujarat, Maharashtra, Karnataka, Kerala etc. A wind farm is also located at Kanyakumari which is the farthest point of Indian mainland.

The major hindrances in development of these energy sources are as follows:

1. Environmental degradation of the area.

2. Availability of areas where the moving wind or flowing water is available.

3. Transportation of equipment to the selected area.

4. Heavy initial investment.

(i) Ocean thermal energy due to difference in water’s temperature at surface and deep inside the water.

(ii) This form of energy is ultimately derived from sun because it is the sun rays which are causing the upper surface of the ocean to heat up and cause the temperature difference.

(iii) The warm water of the surface is used to boil a volatile liquid like ammonia and the vapors of the liquid cause the turbine to rotate and the cold water the lower levels are used to condense this gas to turn it to liquid and the process continues.

(i) The values displayed by Mr. Nair. Nikhil and Neha are as follows:

1. Energy from renewable source of energy

2. Energy production does not contribute to pollution.

They all possess high degree of general awareness, helping nature and at the same they are nature conserver.

(ii) The possible arguments are as follows:

1. Economic and cheaper way to generate fuel

2. Use of your own organic and agricultural waste to generate fuel.

3. Efficient burning of biogas as compared to other fuels.

4. The slurry from biogas plant can be used as fertilizer for the fields.

5. Burning biogas does not pollute environment and also leaves no ash.

(i) Biogas is an excellent fuel for cooking purposes and it also contains 75% of methane because of which biogas burns without giving any kind of smoke and also do not leave any residue after being heated.

Since biogas also uses wastewater, it removes the oxygen-demanding pathogens present in the waste thereby preventing the pollution of water bodies.

Biogas plants contain the residue after all the organic matter is converted to gas. This residue is rich in phosphorous and nitrogen which are the two main nutrients for plants. Hence this residue can be used as an organic fertilizer for plants.

Biogas is a cheaper and economic way for villagers to obtain cooking fuel.

(ii) Bio gas is the gas formed in the biogas plant due to anaerobic oxidation of organic material. But the majority or the starting material for the biogas plant in India is the cow dung which is known as “gobar” in Hindi Language and hence the gas formed in the biogas plant is termed as the “gobar gas”

(iii) The villagers were very much impressed because of following reasons:

1. For generation of biogas the raw material is all the organic and agricultural waste which is readily available in their homes.

2. The slurry from biogas plant can be used as fertilizer for the fields as it is rich in phosphorous and nitrogen.

3. Efficient burning of biogas as compared to other fuels.

The material mined from earth and when heated strongly in an insufficient supply of air gives a solid fuel which is rich in carbon indicates that the material P is also very rich in carbon and hence the material has to be coal because coal is mined from earth and on incomplete combustion it gives a solid fuel.

The solid fuel Q is coke.

R obtained from trees which signify that wood is the only tree part which when heated in insufficient supply of oxygen gives a carbon-rich compound.

S obtained on burning wood is charcoal.

But none of the options match with our answers.

So correct answer is D.

Given:

Power = 100 W/m²

Mass of water = 30 kg

Time = 30 minutes

Specific Heat of Water = 4200 J/kg °C

Solution:

Heat Generated = Mass × Specific Heat × Temperature Rise.

Heat Generated = Power × time

Mass × Specific Heat × Temperature Rise = Power × time

Temperature Rise = 1.43 °C

So correct answer is C.

Ethanethiol is added to LPG in cylinders so that the leak of the LPG gas from the cylinders becomes noticeable quickly as ethanethiol has very foul smell. The structure is as follows:

So the correct answer is B.

Given:

Total energy released per minute = 48 kJ

= 48 × 10³ J

Energy produced per second

= 0.8 × 10³ J

Energy release per fission = 3.2 x 10^-11 J

Solution

= 2.5x10¹³

Therefore number of fission per second is 2.5x10¹³.

So the correct answer is D.

Elements with greater mass number indicate that their nucleus is highly unstable and when such nucleus is bombarded with a moving particle, it splits the nucleus easily.

So the correct answer is D.