[Physics Class Notes] on Infrared Radiation Pdf for Exam

What are Infra-Red Radiations?

The infrared radiation wavelength ranges between 700 nanometers and one millimeter. They have a longer wavelength than visible light and have a frequency of about 300 to 400 GHz.

The infrared radiation definition is crucial in understanding related concepts and its applications as well. Hence, students should note here that infrared radiations are not visible to the naked eye. Instead, they can only be felt by a human in the form of heat. 

Although infrared rays have specific properties similar to that of light rays, they are not the same. Features like polarising, reflection, etc. can be observed with infrared radiations.

What are the Uses of Infrared Radiations?

Before delving into the infrared radiation uses, students should be clear about a vital aspect. Infrared radiations are put into applications in two forms – rays and waves. The sources of infrared radiation and visible light are the heat or thermal rays. 

In broad terms, it is the sun and fire that are the prime sources of infrared radiations. 

However, they are trapped and used in multiple areas, including medical applications.

• The other applications include infrared radiation uses in physical therapy. It warms the body and helps in muscle relaxation. 

• The rays are also used in photography. Usually, digital cameras use this technique to click images. 

Out of all these applications, the infrared radiation therapy in both muscle relaxations and medical areas have gained immense significance. It is also hoped that the recent advancements will lead to further areas of applications.  

So, after reading the above lesson, students should also be able to answer the following questions. Give it a try for yourself and assess your knowledge.

Test Your Learning So Far

Fill in the blanks

1. Infrared radiations have a wavelength higher than …………. nm.

2. The visible spectrum has a wavelength ……….… than infrared radiation.

3. X-rays have a wavelength ………….. than infrared radiation.

4. ………… radiations are also called thermal waves.

5. Infrared rays have a wavelength nearing …….…. Hz.

Answers: 700, longer, shorter, Infrared, 300 to 400

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