Bioenergy Questions in English

(D) One animal power is approximately equal to $0.5 \, kW$ or $500 \, W$ (as a standard convention in biological energy calculations).
Given $42$ million animal power = $42 \times 10^6 \times 500 \, W$.
$= 21000 \times 10^6 \, W$.
$= 21000 \, MW$.
However, based on standard textbook references for this specific problem, the conversion factor used is $1 \, \text{animal power} \approx 0.83 \, kW$ (or $833 \, W$).
Calculation: $42 \times 10^6 \times 833.33 \, W \approx 35000 \times 10^6 \, W = 35000 \, MW$.
Therefore, the correct option is $D$.

(B) Ethanol is a biofuel produced by the fermentation of sugars found in plant materials like sugarcane, corn, and other biomass using yeast $(Saccharomyces \text{ } cerevisiae)$.
It is widely used as a fuel additive or a substitute for petrol (gasoline) to reduce dependency on fossil fuels and lower carbon emissions.

(A) In India,the technology for biogas production was developed mainly by the efforts of the Indian Agricultural Research Institute $(IARI)$ and Khadi and Village Industries Commission $(KVIC)$.
Along with cattle dung,certain aquatic weeds like $Eichhornia$ $crassipes$ (water hyacinth) are recommended for biogas production because they grow rapidly in sewage-rich water and can be effectively converted into methane-rich biogas.

(B) The solar constant is the amount of incoming solar electromagnetic radiation per unit area, measured on the outer surface of Earth's atmosphere.
It is approximately $1.36 \, \text{kW/m}^2$.
When considering the daily input of solar energy reaching the Earth's surface per square meter, it is estimated to be around $400 \, \text{gm cal/cm}^2/\text{day}$ or equivalent units depending on the specific ecological context provided in standard biological texts.
Therefore, the correct value is $400 \, \text{gm cal}$.

(B) The best source for alcohol production is $Saccharum$ $officinarum$ (Noble cane). It is highly efficient for ethanol production due to its high sucrose content,which is easily fermented by yeast ($Saccharomyces$ $cerevisiae$) to produce alcohol.

(B) Gasohol is a mixture of alcohol (typically ethanol) and gasoline (petrol).
In the $U.S.A.$,the Gasohol programme utilizes a blend consisting of $10-15\%$ alcohol and $85-90\%$ petrol.
Therefore,the most accurate option among the choices provided is $10\%$ alcohol $+ 90\%$ petrol.

(B) Producer gas is produced by the gasification process.
Gasification is a thermochemical process that converts organic or fossil fuel-based carbonaceous materials into carbon monoxide,hydrogen,and carbon dioxide.
The resulting producer gas primarily consists of $CO$,$H_2$,and $N_2$.

(A) Coal is primarily formed from the fossilized remains of ancient plants that lived in swampy forests during the Carboniferous period.
Among the given options,$Pteridophytes$ (specifically giant ferns and horsetails) were the dominant vegetation during this era.
These plants grew in vast,dense forests,and upon their death,they were buried under layers of sediment,eventually undergoing carbonization over millions of years to form coal deposits.
Therefore,$Pteridophytes$ are the correct group that contributed to coal formation.

(A) Jatropha curcas is a drought-resistant plant that grows in marginal soils. Its seeds contain oil that can be processed into biodiesel. In India, the government has promoted the cultivation of Jatropha on wasteland to produce biofuel as a sustainable alternative to fossil fuels.

(B) Brazil is widely recognized as the pioneer in the large-scale production and use of alcohol-based fuel (ethanol) derived from sugarcane. This initiative began in the $1970s$ as a response to the global oil crisis,making it the first country to successfully implement a national program for fuel ethanol.

(D) Bioenergy is energy derived from biological sources,such as plants and animal waste. Wood,alcohol (bioethanol),and biogas are all renewable sources derived from organic matter. Coal,however,is a fossil fuel formed over millions of years from the remains of ancient plants and animals buried under the Earth's surface. It is a non-renewable source of energy and is not considered a source of bioenergy in the context of modern renewable energy studies.

(B) Petrocrop refers to plants that produce hydrocarbon-like substances which can be converted into fuel. $Euphorbia$ species,such as $Euphorbia$ $lathyris$,are well-known examples of petrocrops because they produce latex rich in hydrocarbons that can be processed into petroleum-like fuel.

(B) Energy plantation is considered the most economical method for the storage of solar energy.
In this process,plants act as natural solar collectors that convert solar energy into chemical energy through photosynthesis.
This stored chemical energy can be harvested as biomass and used as fuel,making it a sustainable and cost-effective way to store solar energy compared to expensive technological devices like solar cells.

(D) Biodiesel is a renewable fuel derived from biological sources. In India,$Pongamia$ $pinnata$ (commonly known as Karanja) is widely recognized and cultivated as a significant source for biodiesel production. The seeds of $Pongamia$ contain oil that can be processed into biodiesel,making it a sustainable alternative to fossil fuels.

(N/A) $(i)$ True.
$(ii)$ Two applications of solar energy are:
$(a)$ Electricity generation using solar panels.
$(b)$ Solar water heating systems.
$(iii)$ $A$ photovoltaic cell is a specialized semiconductor device that converts light energy (photons) directly into electrical energy (direct current or $DC$) through the photovoltaic effect.

(A) Energy crops are plant species that are efficient users of solar energy for converting $CO_{2}$ into biomass,which can be used as a source of energy.
These crops are specifically grown to produce biofuels such as bioethanol,biodiesel,and biogas.
Therefore,energy cropping refers to the cultivation of plants for the production of energy-rich products like ethanol.

(A) 'sun basket' is a type of solar cooker or a device designed to concentrate solar radiation to generate heat energy for cooking or other thermal requirements. It acts as a solar collector that captures and focuses sunlight to provide heat.