Incandescence
Incandescence
The emission of light by a substance due to high temperatures: white or bright-red heat. When objects such as iron placed in fire it become dull red by 700 C degree. From 700 C degree to 1500 C degree, the color shifted from red to orange and definitely yellow; by the time the iron melts. Objects higher than 1500 C degree will be seen white such as sun surface on the day, which has a temperature of about 5700 C degree. This white color is called white hot. When temperature increasing caused by energy increasing, the object emitted colored light from black body to red and yellow to bluish-white depend on energy increasing. It means hotter the object therefore more vibration energy of the atom and higher the frequency of the light in equilibrium with it.