All questions of Greenhouse Effect for Grade 10 Exam

Greenhouse Gases

Greenhouse gases are gases that trap heat in the Earth's atmosphere, contributing to the greenhouse effect. They absorb and emit infrared radiation, which leads to an increase in the Earth's surface temperature. Some of the most common greenhouse gases include carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), and chlorofluorocarbons (CFCs).

Efficiency of Greenhouse Gases

The efficiency of a greenhouse gas refers to its ability to absorb and emit infrared radiation, which determines its potency in contributing to the greenhouse effect. The higher the efficiency, the more heat the gas can trap and the stronger its warming potential.

CFCs - Chlorofluorocarbons

Chlorofluorocarbons, or CFCs, are a group of synthetic compounds that contain chlorine, fluorine, and carbon atoms. They were commonly used in refrigerants, aerosol propellants, and foam-blowing agents until their production was phased out due to their harmful effects on the ozone layer.

CFCs have a very high efficiency as greenhouse gases. They are characterized by their long atmospheric lifetimes, which can range from several decades to centuries. During their lifespan, CFCs can absorb and re-emit a significant amount of infrared radiation, leading to a strong greenhouse effect.

Other Greenhouse Gases

While CFCs are highly efficient greenhouse gases, other gases also contribute to the greenhouse effect.

- N2O: Nitrous oxide, also known as laughing gas, is a potent greenhouse gas produced by agricultural and industrial activities. It has a lower efficiency compared to CFCs but still contributes significantly to the greenhouse effect.

- CO2: Carbon dioxide is the most well-known greenhouse gas and is primarily emitted through the burning of fossil fuels and deforestation. It has a lower efficiency than both CFCs and N2O but is the most abundant and long-lasting greenhouse gas.

- CH4: Methane is another important greenhouse gas, primarily emitted by natural processes, such as the decomposition of organic matter and the digestive systems of livestock. It has a lower efficiency than CFCs but a higher warming potential than CO2.

Conclusion

In conclusion, while there are several potent greenhouse gases, CFCs are considered to be the most efficient in terms of their ability to trap heat and contribute to the greenhouse effect. However, it is important to note that the overall impact of a greenhouse gas also depends on its concentration in the atmosphere and its lifetime.

Higher energy level and shorter wavelength are characteristics of ultraviolet radiation.

Explanation:
- Ultraviolet radiation: Ultraviolet (UV) radiation is a type of electromagnetic radiation with a higher energy level and shorter wavelength than visible light. It is located between X-rays and visible light on the electromagnetic spectrum. UV radiation is not visible to the human eye but can be detected using specialized equipment.

Characteristics of ultraviolet radiation:
1. Higher energy level: Ultraviolet radiation has a higher energy level compared to visible light. This higher energy is due to the shorter wavelength of UV radiation. The energy of electromagnetic radiation is directly proportional to its frequency or inversely proportional to its wavelength. Therefore, as the wavelength of UV radiation decreases, its energy level increases.

2. Shorter wavelength: Ultraviolet radiation has a shorter wavelength than visible light. The wavelength of UV radiation ranges from about 10 nanometers (nm) to 400 nm, whereas visible light ranges from approximately 400 nm to 700 nm. The shorter wavelength of UV radiation corresponds to higher frequencies and energies.

Comparison with other options:
- Infrared radiation: Infrared radiation has a longer wavelength and lower energy level than visible light. It is located between microwaves and visible light on the electromagnetic spectrum.
- Alpha radiation: Alpha radiation consists of alpha particles, which are helium nuclei. It is a type of ionizing radiation but does not have a characteristic energy level or wavelength.
- Beta radiation: Beta radiation consists of beta particles, which are high-energy electrons or positrons. It is also a type of ionizing radiation but does not have a characteristic energy level or wavelength.

Conclusion:
Among the given options, ultraviolet radiation (option D) has higher energy levels and shorter wavelengths. UV radiation is an important component of sunlight and has various applications in medicine, industry, and research.

The correct answer is c) 33.

Naturally Occurring Greenhouse Gases

Naturally occurring greenhouse gases are those that are present in the Earth's atmosphere as a result of natural processes and are essential for maintaining the Earth's temperature. These gases trap heat from the sun and contribute to the greenhouse effect, which is necessary for supporting life on Earth. They include carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), and several others.

Explanation of the Options

a) CFCs (chlorofluorocarbons): CFCs are synthetic compounds that were commonly used in various products, such as aerosol sprays and refrigerants. They were primarily manufactured by humans and have been phased out due to their harmful impact on the ozone layer. While CFCs do contribute to global warming when released into the atmosphere, they are not classified as naturally occurring greenhouse gases.

b) Methane: Methane is a naturally occurring greenhouse gas that is released through natural processes such as the decomposition of organic matter, agricultural activities, and the digestion process of livestock. It is a potent greenhouse gas and has a greater warming effect compared to carbon dioxide.

c) Carbon dioxide: Carbon dioxide is a naturally occurring greenhouse gas that is released through natural processes such as respiration, volcanic activity, and the decay of organic matter. It is also emitted through human activities such as burning fossil fuels. Carbon dioxide is the most significant greenhouse gas in terms of its contribution to global warming.

d) Nitrous oxide: Nitrous oxide is a naturally occurring greenhouse gas that is released through natural processes such as bacterial processes in soils and oceans, as well as human activities such as agriculture and industrial processes. It is a potent greenhouse gas, with a warming effect over 300 times that of carbon dioxide.

Conclusion

In conclusion, the option that is not considered a naturally occurring greenhouse gas is a) CFCs. While CFCs do contribute to global warming, they are synthetic compounds primarily produced by human activities and have been phased out due to their harmful impact on the ozone layer. The other options, methane, carbon dioxide, and nitrous oxide, are all naturally occurring greenhouse gases that play significant roles in the Earth's climate system.

Explanation:

Wavelength of Infrared Radiation:
Infrared radiation has a longer wavelength compared to visible light. It falls between the visible and microwave regions of the electromagnetic spectrum.

Longer Wavelength:
Infrared radiation has longer wavelengths that range from about 700 nanometers to 1 millimeter. These longer wavelengths allow infrared radiation to penetrate materials like clothing and skin, producing heat.

Heat Sensing:
Infrared radiation is commonly used for heat sensing and thermal imaging because it can detect the heat emitted by objects and living organisms.

Applications:
Infrared radiation is used in various applications such as night vision devices, remote sensing, communication, and heating. It plays a crucial role in many scientific and technological fields.

Conclusion:
In conclusion, the wavelength of infrared radiation is longer compared to visible light, making it suitable for heat sensing and various applications in science and technology.

B) the greenhouse effect is a natural process that maintains the earth.

The greenhouse effect is not a natural process; it is primarily caused by human activities that release greenhouse gases into the atmosphere, such as burning fossil fuels. While it is true that life on Earth is possible due to the greenhouse effect, attributing it solely to a natural process is inaccurate.