Q. 1. What do you mean by energy?
Energy is the measure of a physical system. It defines the quality of the changes and processes which take place in the Universe, beginning with movement and finishing with thinking.
Q.2. Define electromagnetic radiation.
Electromagnetic (EM) radiation is a self-propagating wave in space or through matter. Electromagnetic radiation consists of discrete packets of energy, which we call photons. A photon consists of an oscillating electric field component, E, and an oscillating magnetic field component, M. The electric and magnetic fields are orthogonal (perpendicular) to each other, and they are orthogonal to the direction of propogation of the photon.
Q.3. Write a short note on:
i. Wind energy
I. Wind energy is one of the most potential sources of alternate energy, which is strangely influenced by geographical factors. Wind energy is harnessed by using wind mills. Wind mill is driven by the energy of sun. Making use of this energy, the blade of the wind mill keep on rotating due to the force of striking wind.
Once the mill is turning due to force of wind, it cans even a generator to get electricity. It is a non-polluting and sustainable source of energy but it is variable, unsteady, irregular, intermittent and erratic.
II. Bio-energy -materials obtaining from the physiological activities is known as biomass. Biomass includes plant residues, wastes, herbarium plants, fresh water and marine algae and forest residue, etc. this biomass may be utilised for the generation of a number of energy system which are renewable source of energy.
III. Hydropower energy-the water flowing in a river is collected by constructing a big dam where the water is stored and allowed to fall from a height. The blades of the turbine located at the bottom of the dam move with the fast moving water which in turn rotates the generator and produces electricity.
Hydropower does not cause any pollution, it is renewable and normally the hydro power projects are multi-purpose projects helping in controlling floods, used for irrigation, navigation etc.
Q.4. There is how many types of coal?
There are mainly three types of coal. Lignite is the lowest rank of coal with the lowest energy content. Lignite is crumbly and has high moisture content. Lignite is mainly burned at power plants to generate electricity. Bituminous coal contains 45-86 per cent carbon, and has two to three times the heating value of lignite.
Bituminous coal was formed under high heat and pressure. Bituminous coal is used to generate electricity and is an important fuel and raw material for the steel and iron industries. Anthracite contains 86-97 per cent carbon, and has a heating value slightly lower than bituminous coal.
Q.5. What are the uses of natural gas?
Natural gas is an essential raw material for many common products, such as: paints, fertilizer, plastics, anti-freeze, dyes, photographic film, medicines, and explosives. It’s used to produce steel, glass; paper, clothing, brick, electricity and homes use natural gas to fuel stoves, furnaces, water heaters, clothes dryers and other household appliances. It is also used to roast coffee, smoke meats, bake bread and much more.
Q.6. What is the affect of natural gas on environment?
As with other fossil fuels, burning natural gas produces carbon dioxide, which is the most important greenhouse gas. Natural gas also affects the environment when it is produced, stored and transported. Because natural gas is made up mostly of methane (another greenhouse gas), small amounts of methane can sometimes leak into the atmosphere from wells, storage tanks and pipelines.
Q.7. How will you differentiate nuclear fusion and nuclear fission?
In nuclear fusion, energy is released when atoms are combined or fused together to form a larger atom. This is how the sun produces energy where as in nuclear fission, atoms are split apart to form smaller atoms, releasing energy. Nuclear power plants use nuclear fission to produce electricity.