Science Olympiad Test: Sources of Energy-2 - Class 10 MCQ

We know that windmills are used to generate power from the winds. It converts wind energy to electrical energy. The power generated in a windmill depends on the velocity of the wind. If the velocity of the wind is higher, the windmill will generate more power. If the velocity of the wind is lower, the windmill will produce less power. In general, wind speed requires a minimum of 8 kph (2 m/s) to start rotating most small wind turbines. Hence, we can see that the power generated in a windmill depends on the velocity of the wind.

Wind power, P = πr² ρv³, where, v is the speed and pv is density of air.

Solar cell is made of silicon which is a good semiconductor.

Suitable technologies are being developed to overcome difficulties in the way of using hydrogen as a fuel in near future.

Coke LPG are secondary fuels whereas wood and petroleum are primary fuels.

Petroleum on fractional distillation yields diesel, kerosene, petrol or gasoline, petroleum gas, asphalt, lubricating oil, paraffin wax.

• Biogas is formed by the decomposition of organic matter with the action of bacteria in the absence of oxygen.
• The components in biogas is as follows: Methane 50-75%, Carbon dioxide 25-50%, Nitrogen 0-10%, Hydrogen 0-1%.

Hence, methane is the major component in biogas.

Solar energy is the energy that we receive from the sun. Therefore, the heater will not get enough solar energy and the water will not heat. On a cloudy day, heat radiation coming from the sun do not reach the solar water heater. Hence, the solar water heater cannot be used to heat water on a cloudy day.

• A renewable resource is a source of energy which can be used repeatedly and replaced naturally. Sun, tidal waves and wind are renewable resources for solar energy, tidal energy and wind energy respectively.
• Non-renewable energy comes from sources that will run out or will not be replenished in our lifetime. Most non-renewable energy sources are fossil fuels: coal, petroleum, and natural gas.

A nuclear fuel is the fuel that is used in a nuclear reactor to sustain a nuclear chain reaction. These fuels must be fissile and contain heavy radioactive nuclei such as uranium-235 and plutonium-239 to maintain a nuclear chain reaction.

Natural gas gives off 50% of the CO₂ released by coal and 25% less CO₂ than oil for the same amount of energy produced.

Kerosene has the highest calorific value of all and is thus used in a jet aeroplane as an aviation fuel.

The heavier fraction of LPG is containing propane, butane, pentane etc. may be liquefied under pressure to produce liquefied petroleum gas.
So, LPG gas is basically propane and butane, and it is odorless in its natural state. The smell that you notice when there is a leak is actually the stench of an entirely different agent, called ethyl mercaptan (C₂H₆S)(C₂H₆S). This substance is added to the gas when it leaves the main storage terminals.
This substance is added in order to detect the leakage of LPG at the household level in order to save from fire accidents.
Hence, the strong-smelling substance added to LPG is ethyl mercaptan.

The hydrogen bomb relies on fusion, the process of taking two separate atoms and putting them together to form a third atom.
Fusion is the process that powers the sun and the stars. It is the reaction in which two atoms of hydrogen combine together, or fuse, to form an atom of helium. In the process some of the mass of the hydrogen is converted into energy.

Hydrogen fuel is the most promising alternative fuel for the future. It has a high calorific value. and its only combustion product is water, so it is pollution free. It yields almost double the energy provided by jet fuels.
But it is not used as domestic fuel, due to several reasons:

• Hydrogen is not easily available and cost of production is high Unlike other gases, hydrogen is not readily available in the atmosphere. It requires processes like electrolysis of water for its production. This is a very costly process and time-consuming
• It is not easy to store: First of all, hydrogen is a gaseous fuel. Gases are less dense i.e. they occupy more volume. So, hydrogen requires a large fuel tank for storage.
• Hydrogen is highly explosive: Using it as domestic fuel is very dangerous, because even a small spark can cause uncontrolled combustion leading to huge explosions.
• It does not burn at a slow rate
• Transport of hydrogen is very difficult.