Science, asked by sawan9544, 1 year ago

Electromagnetic waves class 12 important questions

Answers

Answered by AJAYMAHICH
1
1.To which part of the electromagnetic spectrum does a wave of frequency 5 x 1019 Hz belong

2.Write the condition under which an electron will move undeflected in the presence of crossed electric and magnetic fields.



3.Name the electromagnetic waves which
(i) maintain the earth’s warmth and
(ii) are used in aircraft navigation. 


4.Write two uses of microwaves. 



5. Write two uses of infrared rays.



6. What is the frequency of electromagnetic waves produced by oscillating charge of frequency V=105Hz?  



7. Arrange the following in descending order of wavelength. X-rays, radiowaves, blue light, infrared light. 





8.Identify the   following electromagnetic radiations as per the frequencies given below. Write one application of each.

1020 Hz

1012 Hz

10n Hz


9.How are electromagnetic waves produced by oscillating charges? Why is it not possible to produce electromagnetic waves in the visible region with modern electronic circuits in the laboratory? What is the method of production of X-rays? 



10.(i) Describe briefly how electromagnetic waves are produced by oscillating charges? (ii) Give one use of each of the following.

Microwaves

Ultraviolet rays

Infrared rays

y-rays 



11.Answer the following questions
(i) Name the EM waves which s suitable for radar systems used in aircraft navigation. Write the range of frequency of these waves.
(ii) If the earth did not have atmosphere, would its average surface temperature be higher or lower than what it is now? Explain.
(iii) An EM wave exerts pressure on the surface on which it is incident. Justify.   



12.Name the electromagnetic radiations having the wavelength range from 1 nm to 10~3 Give its two important applications. 



13.Draw a sketch of a plane electromagnetic wave propagating along the Z-direction. Depict clearly the directions of electric and magnetic fields varying sinusoidally with Z. 




 






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