Chapter 14 . Sources of Energy

Class 10 Science Chapter 14 . Sources of Energy Internal Questions and Answers :

1. What is a good source of energy?

Answer: A good source of energy is one that is sustainable, clean, and efficient. Examples include renewable energy sources like solar power, wind power, hydroelectric power, and geothermal energy. Additionally, energy conservation and efficiency measures can also contribute to a sustainable energy system .
2. What is a good fuel?

Answer: A good fuel is one that has a high energy content, is readily available, easy to store and transport, and produces minimal harmful emissions or pollutants when burned.
3. If you could use any source of energy for heating your food, which one would you use and why ?

Answer: : If given the choice, I would prefer to use electricity as a source of energy for heating food. Electricity is versatile, clean, and readily available in most households, making it convenient and efficient for heating purposes.

Internal Questions :

1. What are the disadvantages of fossil fuels?

Answer:  The disadvantages of fossil fuels are :

(i) Environmental Impact: Fossil fuel combustion releases greenhouse gases, contributing to climate change and air pollution.

(ii). Depletion of Resources: Fossil fuel reserves are finite and non-renewable.

(iii). Geopolitical Issues: Dependence on fossil fuels can lead to geopolitical conflicts over resources.

(iv). Health Risks: Fossil fuel extraction and combustion can result in health hazards for workers and nearby communities.

(v). Price Volatility: Fossil fuel prices can be unpredictable and subject to fluctuations due to market factors.

2. Why are we looking at alternate sources of energy?

Answer:  We are looking at alternate sources of energy due to several reasons:

(i). Environmental Concerns: To reduce greenhouse gas emissions and combat climate change.

(ii). Energy Security: To diversify energy sources and reduce dependence on finite fossil fuels.

(iii). Sustainable Development: To promote sustainable and long-term energy solutions.

3. How has the traditional use of wind and water energy been modified for our convenience?

Answer: The traditional use of wind and water energy has been modified for convenience through the development of technologies such as wind turbines and hydroelectric power plants. These technologies efficiently harness wind and water energy to generate electricity, providing a reliable and convenient source of renewable energy.

Internal Questions :

1. What kind of mirror – concave, convex or plain – would be best suited for use in a solar cooker? Why?

Answer: A concave mirror would be best suited for use in a solar cooker. A concave mirror can converge sunlight to a focal point, allowing for concentrated heat generation, which is essential for efficient cooking in a solar cooker.
2. What are the limitations of the energy that can be obtained from the oceans?

Answer:  The limitations of obtaining energy from the oceans are:

(i). High Capital Costs: Building and installing ocean energy systems can be expensive, limiting widespread deployment.

(ii). Environmental Impact: Some ocean energy technologies may have adverse effects on marine ecosystems and wildlife.

(iii). Variability and Intermittency: Ocean energy availability can be influenced by tides, waves, and weather conditions, leading to intermittent power generation.

(iv). Technical Challenges: Developing and maintaining reliable and efficient ocean energy systems pose technical challenges, such as corrosion, fouling, and durability in harsh marine environments.

3. What is geothermal energy?

Answer: Geothermal energy is a form of renewable energy derived from the heat stored beneath the Earth's surface. It involves utilizing the natural heat from the Earth's interior to generate electricity or provide direct heating and cooling.
4. What are the advantages of nuclear energy?

Answer: Advantages of nuclear energy are :

(i). High Energy Density: Nuclear fuel provides a concentrated energy source, resulting in a smaller amount of fuel required for a given energy output.

(ii).  Low Greenhouse Gas Emissions: Nuclear power plants produce minimal greenhouse gas emissions, contributing to climate change mitigation.

(iii). Base Load Power: Nuclear plants provide a consistent and reliable baseload power supply.

(iv). Fuel Availability: Abundant uranium reserves ensure a stable fuel supply for the foreseeable future.

(v). Energy Independence: Nuclear energy reduces dependence on fossil fuel imports for energy production.

Internal Questions :

1. Can any source of energy be pollution-free? Why or why not?

Answer: No source of energy can be completely pollution-free. While renewable sources like solar and wind have minimal operational emissions, they may have indirect environmental impacts during manufacturing, installation, and disposal. However, their environmental footprint is significantly lower compared to fossil fuels.
2. Hydrogen has been used as a rocket fuel. Would you consider it a cleaner fuel than CNG? Why or why not?

Answer: Hydrogen can be considered a cleaner fuel than Compressed Natural Gas (CNG) because its combustion produces only water vapor as a byproduct. In contrast, CNG combustion releases carbon dioxide (), a greenhouse gas that contributes to climate change.

Internal Questions :

1. Name two energy sources that you would consider to be renewable. Give reasons for your choices.

Answer: Two renewable energy sources are solar power and wind power.

Solar Power: It harnesses energy from the sun, which is abundant and inexhaustible. Solar panels convert sunlight directly into electricity without producing greenhouse gas emissions.

Wind Power: It utilizes the kinetic energy of wind to generate electricity. Wind is a natural and renewable resource, and wind turbines have no fuel consumption or emissions during operation, making it environmentally friendly.

2. Give the names of two energy sources that you would consider to be exhaustible. Give reasons for your choices.

Answer: Two energy sources that are considered exhaustible are fossil fuels (such as coal, oil, and natural gas) and nuclear fuel.

Fossil Fuels : They are formed over millions of years and are being consumed at a much faster rate than they can be replenished. Once depleted, they cannot be readily replaced.

Nuclear Fuel : Although there are significant reserves of uranium, the primary fuel for nuclear power, it is still a finite resource. The extraction and processing of uranium also have environmental impacts, making it exhaustible in the long term.

Class 10 Science Chapter 14 . Sources of Energy Exercises  :

1. A solar water heater cannot be used to get hot water on
(a) a sunny day. (b) a cloudy day.
(c) a hot day. (d) a windy day.

Answer: (b) a cloudy day .
2. Which of the following is not an example of a bio-mass energy source?
(a) wood (b) gobar-gas
(c) nuclear energy (d) coal

Answer: (c) nuclear energy .
3. Most of the sources of energy we use represent stored solar energy. Which of the following is not ultimately derived from the Sun’s energy?
(a) geothermal energy (b) wind energy
(c) nuclear energy (d) bio-mass.

Answer: nuclear energy .
4. Compare and contrast fossil fuels and the Sun as direct sources of energy.

Answer:  Fossil fuels are finite, formed from ancient organic matter, and produce greenhouse gases. The Sun provides renewable energy through solar radiation, is abundant, and does not emit harmful gases. Fossil fuels contribute to climate change, while solar energy helps reduce environmental impact and dependence on limited resources.

5. Compare and contrast bio-mass and hydro electricity as sources of energy.

Answer :  Biomass:

Source: Biomass energy is derived from organic materials like plants, agricultural waste, or wood.

Conversion: It is converted into energy through combustion or biochemical processes.

Impact: Biomass can produce emissions and air pollution.

Availability: Biomass is generally available locally.

Hydroelectricity:

Source: Hydroelectricity is generated from flowing water in rivers or dams.

Conversion: It is converted into electricity using turbines.

Impact: Hydroelectricity is clean and produces no direct emissions.

Availability: It relies on water resources and suitable locations for dams.

6. What are the limitations of extracting energy from—
(a) the wind? (b) waves? (c) tides?

Answer: (a) Wind Energy: Intermittent supply, location-dependent, visual and noise impact, high upfront costs.

(b) Wave Energy: Location-specific, technology challenges, environmental impact, maintenance needs.

(c) Tidal Energy: Site-specific, environmental impact, high construction costs, limited energy output.

7. On what basis would you classify energy sources as
(a) renewable and non-renewable?
(b) exhaustible and inexhaustible?
Are the options given in (a) and (b) the same?

Answer:  (a) Renewable and Non-Renewable:

Renewable energy sources can be naturally replenished in a relatively short time, like solar and wind energy.

Non-renewable energy sources are finite and deplete over time, such as fossil fuels like coal and oil.

(b) Exhaustible and Inexhaustible:

Exhaustible energy sources are finite and will eventually be used up, like fossil fuels.

Inexhaustible energy sources have an endless supply and will not run out, like solar and wind energy.

The options in (a) and (b) are not the same. Renewable sources can be either inexhaustible (e.g., solar, wind) or exhaustible (e.g., biomass), depending on their nature and usage. Non-renewable sources are always exhaustible.

8. What are the qualities of an ideal source of energy?

Answer:  The qualities of an ideal source of energy are :

Sustainability: It should be renewable or have a practically unlimited supply.

Environmental Compatibility: It should have minimal or no emissions, reducing ecological impact.

Efficiency: It should convert energy with high efficiency to maximize output.

Accessibility: It should be readily available and accessible for widespread use.

Affordability: It should be economically viable for affordability and accessibility to all.

9. What are the advantages and disadvantages of using a solar cooker? Are there places where solar cookers would have limited utility?

Answer:  Advantages of using a solar cooker:

I. Renewable Energy: Solar cookers utilize clean and renewable energy.

II. Cost-effective: No fuel costs are incurred.

III. Environmentally Friendly: They produce no emissions or pollution.

IV. Simple Operation: Easy to use and maintain.

Disadvantages:

I. Weather Dependence: Solar cookers require sunny conditions.

II. Slower Cooking: Cooking times may be longer.

III. Limited Cooking Options: Certain cooking methods may be challenging.

Solar cookers would have limited utility in regions with minimal sunlight, extreme weather conditions, or high population densities with limited outdoor space.

10. What are the environmental consequences of the increasing demand for energy? What steps would you suggest to reduce energy consumption?

Answer: The increasing demand for energy has several environmental consequences, including greenhouse gas emissions, air pollution, habitat destruction, and resource depletion.

To reduce energy consumption, steps can include promoting energy efficiency measures, adopting renewable energy sources, implementing conservation practices, raising awareness about sustainable energy use, and incentivizing responsible energy consumption through policies and regulations.