Characteristics of EM Waves, Class 12 Physics NCERT Solutions

1. There will be total 10  MCQ in this test.
2. Please keep a pen and paper ready for rough work but keep your books away.
3. The test will consist of only objective type multiple choice questions requiring students to mouse-click their correct choice of the options against the related question number.
4. No negative marking for incorrect choice.
5. Please click on “Finish the Test” when you want to exit.
6. All the best – Happy Studying.

1. The speed of electromagnetic waves in free space is given by .
Here μ0 is ___________and ε0 is ________________ of free space.

 permeability, permittivity

 coercivity, permeability

 permeability, susceptibility

 permittivity, permeability

Question 1 of 10

2. Which region in the electromagnetic spectrum will have the highest speed?

 Radio

 Visible

 All the regions have same speed

 Microwaves

Question 2 of 10

3. Which region in the electromagnetic spectrum has the highest frequency?

 Frequency is same for the complete spectrum

 Gamma Radiation Region

 Radio

 Visible

Question 3 of 10

4. Electromagnetic waves constitute of

 Electric and magnetic field varying in space and time sinusoidally and propagating through space such that the two fields are at 60 degrees to the direction of propagation.

 Electric and magnetic field varying in space and time sinusoidally and propagating through space such that the two fields are perpendicular to the direction of propagation.

 Electric and magnetic field varying in space and time tangentially and propagating through space such that the two fields are perpendicular to the direction of propagation.

 Electric and magnetic field varying in space and time tangentially and propagating through space such that the two fields are perpendicular to the direction of propagation.

Question 4 of 10

5. In electromagnetic waves the ratio of amplitudes of electric field and magnetic field is equal to

 (E₀ / 2B₀) = c

 (E₀ / B₀)^1/2 = c

 (2E₀ / B₀) = c

 (E₀ / B₀) = c

Question 5 of 10

6. Which statement is true about electromagnetic waves?

 Electromagnetic waves are longitudinal in nature

 Electromagnetic waves can travel through vacuum

 Velocity of electromagnetic waves is 3 X 10⁹ m/s

 Ratio of electric field and magnetic field in electromagnetic field is 2E_rms / B_rms

Question 6 of 10

7. Which of the following is not a use of electromagnetic wave?

  In detection of invisible writing

 In global warming

  In greenhouses to keep plants warm

 In warfare for looking through mist and fog

Question 7 of 10

8. Which colour of the visible spectrum has the greatest wavelength?

  Blue

 Yellow

 Red

 Violet

Question 8 of 10

9. The electric field for an em wave is: E = E₀sin[(12 x 10¹⁵ t – 4 x 10⁷ x)]. What is the speed of the em waves?

 48 x 10⁸ m / s

 3 x 10⁸ m / s

  4 x 10⁷ m / s

 12 x 10¹⁵ m / s

Question 9 of 10

10. is the electric field of an electromagnetic wave that is propagating in the

 z direction

 x direction

 y direction

 can be any direction

Question 10 of 10

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