Rajasthan BoardEnglish MediumSTD 11 SciencePhysicsThermal Properties of Matter2 Marks
Question
What are thermal radiations? State their important properties.
✓
Answer
Thermal radiation refers to radiant energy emitted by a hot body, which travels through vacuum at a speed of 3 × 108ms-1. Important properties of thermal radiation are as follows:
Thermal radiations do not need any material medium for their propagation and travel in vacuum with a speed of 3 × 108ms-1 i.e., the speed of light.
Thermal radiations travel in straight line and form shadows.
Thermal radiations can be reflected as well as refracted like light radiation.
Thermal radiations do not affect the medium through which they pass.
Thermal radiations obey inverse square law. Thus, intensity of thermal radiation at a surface is inversely proportional to the square of the distance of the given surface from the heat source.
When a body absorbs thermal radiation, its temperature rises.
Thermal radiations are electromagnetic waves whose wavelengths are more than of visible light.
Need a full question paper?
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.