Which layer surrounds the radiative zone and transfers energy from it to the surface via convection currents?

Which layer surrounds the radiative zone and transfers energy from it to the surface via convection currents?

• A. Chromosphere
• B. Radiative zone
• C. Convective zone
• D. Photosphere

Answer: (C)

The key idea is how energy moves outward through a star’s interior. In the Sun, the inner region transfers energy mainly by photons (radiative transfer) in the radiative zone. But as you reach the outer layers, radiative transfer becomes inefficient, and the temperature gradient favors the bulk motion of plasma. Hot material rises toward the surface, cools, sinks, and repeats, creating convection currents. This convective motion forms the convective zone, which surrounds the radiative zone and carries energy upward to the surface. The visible surface is the photosphere, while the chromosphere sits above it—these are atmospheric layers, not the interior energy-transport region. So the layer that surrounds the radiative zone and transfers energy to the surface via convection currents is the convective zone.

The key idea is how energy moves outward through a star’s interior. In the Sun, the inner region transfers energy mainly by photons (radiative transfer) in the radiative zone. But as you reach the outer layers, radiative transfer becomes inefficient, and the temperature gradient favors the bulk motion of plasma. Hot material rises toward the surface, cools, sinks, and repeats, creating convection currents. This convective motion forms the convective zone, which surrounds the radiative zone and carries energy upward to the surface. The visible surface is the photosphere, while the chromosphere sits above it—these are atmospheric layers, not the interior energy-transport region. So the layer that surrounds the radiative zone and transfers energy to the surface via convection currents is the convective zone.