CBSE Class 12 Physics Chapter-8 Important Questions - Free PDF Download
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FAQs on Important Questions for CBSE Class 12 Physics Chapter 8 - Electromagnetic Waves 2024-25
1. How can I ace Chapter 8 of Class 12 Physics?
To prepare for Chapter 8 of Class 12 Physics, students must study from the NCERT book. They should attend all their class lectures including lab lectures so that they clear their doubts with the help of their teachers. They should solve sample papers and NCERT questions for a better understanding of the concepts. Important questions of Chapter 8 of Class 12 Physics can help students to get important questions of Chapter 8 and can also download the PDFs free of cost.
2. What do you understand by the term electromagnetic waves?
The waves which are radiated by an accelerated change propagating through space as coupled as magnetic and electric fields oscillating perpendicular to each other and to the direction of propagation are known as electromagnetic waves. It is also defined as the disturbance produced by both magnetic and electric fields which are mutually perpendicular to each other. The magnetic field which is a time variable is a source of changing electric field. Also, a changing magnetic field is produced from a time-varying electric field.
3. Write down varying properties of the electromagnetic waves.
Some characteristics of electromagnetic waves are listed below:
They do not need any material medium for their transmission.
These waves are transverse in nature.
As these waves travel through space, they carry some energy with them.
The energy carried by the waves are equally shared by electric and magnetic fields.
Electromagnetic waves are carriers of linear momentum when they travel through space.
The principle of superposition is obeyed by these waves.
They do not feel any deflection by magnetic or electric fields.
4. Describe the following keywords for the electromagnetic waves:
Energy density
Intensity
Momentum
Pressure exerted
Energy density –It is defined as the energy of the unit volume in the space through which the wave travels. This energy is equally distributed among the magnetic and electric fields.
Intensity – The energy travelling through per unit time per unit area in the direction of propagation is called the intensity of the wave.
Momentum –For the complete absorption of energy, the transferring of total energy in a time to a surface is known as momentum.
Pressure exerted –Also known as radiation, it is the pressure exerted on the surface when EMW falls.
Vedantu carries a detailed explanation of the Class 12 Chapter 8 to help students understand the concept in an easy fashion.
5. Give a brief introduction about the infrared waves.
The information about the infrared waves is as follows:
They are found in the visible region of the spectrum.
They have long wavelengths and low frequency.
The heating effect is produced by these waves, thus, they are known as thermal radiation or heat waves.
These rays were discovered by William Herschel in 1800.
Properties shown by these waves are diffraction, reflection, refraction, etc.
Small infrared transmitters are fitted in remote controls of TV.
These are used to keep plants warm in greenhouses.
Molecular structures can be studied using these waves.
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