'Solar Energy' is due to-
- AOption (a)
Fusion reaction
- BOption (b)
Fission reaction
- COption (c)
Chemical reaction
- DOption (d)
Combustion reaction
हिंदी में देखें
'सौर ऊर्जा का कारण है-
- (a)
संलयन प्रतिक्रिया
- (b)
विखण्डन प्रतिक्रिया
- (c)
रासायनिक प्रतिक्रिया
- (d)
दहन प्रतिक्रिया
View answer & explanationHide answer & explanation
Correct answer
Fusion reaction
Why this answer is correct
The correct answer is Fusion reaction.
Key Points
- Solar energy is primarily generated by a process called nuclear fusion, occurring at the core of the Sun.
- In the Sun's core, hydrogen nuclei (protons) fuse together to form helium nuclei in a series of nuclear reactions. This process releases an enormous amount of energy in the form of light and heat.
- The primary reaction in the Sun is the proton-proton chain reaction, where hydrogen nuclei combine under extreme temperature (around 15 million °C) and pressure.
- Fusion reactions convert a small portion of matter into energy, as described by Einstein's equation, E = mc², where a small loss of mass results in a significant release of energy.
- This energy is radiated outward from the Sun and reaches Earth as solar radiation, which powers life and various renewable energy systems on the planet.
Additional Information
- Nuclear Fusion vs. Fission:
- Fusion: Involves combining lighter nuclei (e.g., hydrogen) to form a heavier nucleus (e.g., helium), releasing energy. It powers stars like the Sun.
- Fission: Involves splitting heavy atomic nuclei (e.g., uranium or plutonium) into smaller nuclei, releasing energy. It is used in nuclear power plants and atomic bombs.
- Key Conditions for Fusion:
- Extremely high temperature (millions of degrees) to overcome the electrostatic repulsion between positively charged protons.
- High pressure to bring hydrogen nuclei close enough for fusion to occur.
- Such conditions naturally exist in the cores of stars due to their immense gravitational forces.
- Energy Output:
- The Sun emits about 3.8 x 10²⁶ watts of energy every second through fusion reactions.
- Only a fraction of this energy, approximately 1,368 watts per square meter (solar constant), reaches Earth at the top of its atmosphere.
- Applications of Solar Energy:
- Solar energy is harnessed on Earth using technologies like solar panels (photovoltaic cells) and solar thermal systems.
- It is used for electricity generation, water heating, and powering satellites.
- Solar energy is a key component in combating climate change by reducing reliance on fossil fuels.
- Comparison of Options:
- Fusion Reaction: Correct answer, as it explains the process occurring in the Sun's core and the source of solar energy.
- Fission Reaction: Incorrect, as it involves splitting heavy nuclei and does not occur in the Sun.
- Chemical Reaction: Incorrect, as chemical reactions involve electron exchange and are insufficient to produce the Sun's energy.
- Combustion Reaction: Incorrect, as combustion involves burning fuel in the presence of oxygen, which is not the mechanism for solar energy.
Important Points
- Proton-Proton Chain: The Sun primarily uses this process to fuse hydrogen into helium. It is the dominant fusion mechanism in stars of the Sun's size.
- Solar Energy's Role: It is vital for Earth's climate, supporting photosynthesis in plants, driving weather systems, and enabling renewable energy solutions.
- Artificial Fusion: Scientists are working to replicate fusion on Earth (e.g., in tokamaks like ITER), aiming to create a clean and virtually limitless energy source.



