2.6 Black Body Radiation Flashcards
What do all bodies (objects) do?
All bodies (objects), no matter what temperature, emit and absorb infrared radiation
The hotter the body, the ____________ infrared radiation it radiates in a given time
The hotter the body, the more infrared radiation it radiates in a given time
What is a perfect black body?
A perfect black body is an object that absorbs all of the radiation incident on it
What does a black body NOT do?
A black body does not reflect or transmit any radiation
Why would a perfect black body be the best possible emitter?
Because a good absorber is also a good emitter
What does it mean if a body is at a constant temperature?
If a body is at a constant temperature, it is absorbing radiation at the same rate as it is emitting radiation
What does it mean if the temperature of a body increases?
If the temperature of a body increases, then the body absorbs radiation faster than it emits radiation
What does the temperature of the Earth depend on?
The temperature of the Earth depends on many factors, such as:
* The rates of absorption and emission of radiation (i.e. absorption of incoming solar radiation)
* The reflection of radiation into space (i.e. reflection by the surface and atomsphere/clouds)
Give two examples of how an object will reach a point of constant temperature where it is absorbing radiation at the same rate as it is emitting radiation
- The temperature of a hot drink is higher that it’s surroundings so it emits more infrared radiation than it absorbs. The hot drink cools down until it has the reaches temperature as it’s surroundings, so the rate of emission and absorption are the same
- The temperature of a cold drink is lower than its surroundings so it absorbs more infrared radiation than it emits. The temperature eventually rises until it is the the same as the surroundings
