IGCSE/ A-Level Revision Questions

Heat and Light: The Sun is a source of both heat and light because it constantly emits electromagnetic radiation across a wide spectrum, including infrared and visible light. Infrared radiation is perceived as heat, while visible light allows us to see.

Nuclear Fusion in the Core: The Sun produces energy through nuclear fusion in its core. At the Sun's core, the immense pressure and temperature (around 15 million Kelvin) force hydrogen nuclei to fuse together to form helium nuclei. This process releases a tremendous amount of energy according to Einstein's equation, E=mc². A small amount of mass is converted into energy.

Diagram of the Sun's Layers:

Core: The innermost region where nuclear fusion occurs. Energy is released here.

Radiative Zone: Energy from the core is transported outwards by radiation. Photons are constantly absorbed and re-emitted.

Convection Zone: Energy is transported outwards by convection – hot plasma rises, cools, and sinks.

Photosphere: The visible surface of the Sun. This is the layer from which most of the light we see is emitted.

Chromosphere: A layer above the photosphere. It appears reddish in solar eclipses.

Corona: The outermost layer of the Sun's atmosphere. It extends millions of kilometers into space and is extremely hot.

Each layer plays a crucial role in the Sun's energy production and emission.

Physics – 6.2.1 The Sun as a star | e-Consult

6.2.1 The Sun as a star (1 questions)