Which of the following are the characteristics of electromagnetic waves? 1) They are elastic waves. 2) They can also move in a vacuum. 3) They have electric and magnetic components which are mutually perpendicular. 4) They move with speed equal to 3 lakh

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Q: (NDA-II/2019)

Which of the following are the characteristics of electromagnetic waves? 1) They are elastic waves. 2) They can also move in a vacuum. 3) They have electric and magnetic components which are mutually perpendicular. 4) They move with speed equal to 3 lakh meters per second.
Select the correct answer using the code given below:

question_subject: 

Science

question_exam: 

NDA-II

stats: 

0,2,12,6,5,2,1

keywords: 

{'electromagnetic waves': [0, 0, 0, 3], 'elastic waves': [0, 0, 0, 2], 'characteristics': [0, 0, 0, 1], 'magnetic components': [0, 0, 0, 1]}

The correct answer is option 3: 2 and 3 only.

Option 1 states that electromagnetic waves are elastic waves. Elastic waves are mechanical waves that require a medium to propagate, such as sound waves. However, electromagnetic waves are not elastic waves, as they do not require a medium and can propagate through a vacuum. Therefore, option 1 is incorrect.

Option 2 correctly states that electromagnetic waves can move in a vacuum. This is one of the key characteristics of electromagnetic waves. They do not require a medium and can travel through empty space.

Option 3 correctly states that electromagnetic waves have electric and magnetic components that are mutually perpendicular. This characteristic is a defining feature of electromagnetic waves. The electric and magnetic fields of the wave are always at right angles to each other and to the direction of wave propagation.

Option 4 states that electromagnetic waves move with a speed equal to 3 lakh meters per second. This is not accurate. The speed of electromagnetic waves in a vacuum is actually approximately 3 x 10^8 meters per second, which is equal to the speed of light. Therefore, option 4 is incorrect.

In conclusion, option 3 is the correct answer as it accurately describes the characteristics of electromagnetic waves.