Test: Transfer of Thermal Energy - 2 - Year 11 MCQ

Thermal radiation corresponds to the infrared portion of the electromagnetic spectrum. This type of radiation is emitted by all objects and increases with the object's temperature.

Thermal radiation constitutes the sole means by which heat can traverse through a vacuum, such as the heat from the Sun reaching us across the vacuum of space.

The ability of an object to emit and absorb thermal radiation is influenced by its color. For example, dark-colored surfaces are better at emitting and absorbing thermal radiation compared to lighter surfaces.

An object achieves thermal equilibrium when it absorbs and emits radiation at an equal rate. This is the state where the object's temperature remains constant.

Dark-colored surfaces, such as black objects, emit more thermal radiation compared to light-colored surfaces. This is why dark objects are better at absorbing and emitting heat.

Shiny surfaces emit less radiation compared to rough surfaces. This is why shiny objects take longer to cool down compared to rough or dark objects.

If an object receives energy at a slower rate than it releases energy, it will cool down. This is because it is losing heat at a faster rate than it gains energy.

The greenhouse effect warms up the Earth by trapping and redirecting longer-wavelength infrared radiation from the Earth, preventing it from escaping into space, and thus elevating Earth's temperature.

Greenhouse gases trap and redirect longer-wavelength infrared radiation from Earth, which helps in elevating Earth's temperature by preventing the escape of this radiation into space.

The equilibrium between incoming and outgoing radiation on Earth is influenced by factors such as the absorption and emission of radiation. This balance determines Earth's temperature.