Important Questions of Electromagnetic Waves Physics | Zigya

Previous Year Papers

Download Solved Question Papers Free for Offline Practice and view Solutions Online.

Test Series

Take Zigya Full and Sectional Test Series. Time it out for real assessment and get your results instantly.

Test Yourself

Practice and master your preparation for a specific topic or chapter. Check you scores at the end of the test.
Advertisement

 Multiple Choice QuestionsMultiple Choice Questions

Advertisement
21.

Which one of the following statements is wrong ?

  • Radio waves in the frequency range 30 MHz to 60 MHz are called sky waves.

  • Radio horizon of the transmitting antenna for space wave is dT = 2RhT (R = radius of earth, hT = height of transmitting antenna)

  • Within the skip distance neither the ground waves nor the sky waves are received

  • The principle of fibre optical communication is total internal reflection


22.

A plane electromagnetic wave travels in free space along x-axis. At a particular point in space, the electric field along y-axis is 9.3 Vm-1. The magnetic induction is

  • 3.1 × 10-8 T

  • 3 × 10-5 T

  • 3 × 10-6 T

  • 9.3 × 10-6 T


23.

The dielectric constant of air is 1.006. The speed of electromagnetic wave travelling in air is a x 108 ms-1, where a is about

  • 3

  • 3.88

  • 2.5

  • 3.2


24.
  1. The wavelength of microwaves is greater than that of UV-rays.
  2. The wavelength of IR rays is lesser than that of UV-rays.
  3. The wavelength of microwaves is lesser than that of IR rays.
  4. Gamma rays have shortest wavelength in the electromagnetic spectrum.
  5. Of the above statements

  • A and B are true

  • B and C are true

  • A and D are true

  • A and C are true


Advertisement
25.

The frequency of X-rays, γ-rays and ultraviolet rays are respectively a, b and c then

  • a < b, b > c

  • a > b, b > c

  • a > b, b < c

  • a < b, b < c


26.

The waves relevant to telecommunications are

  • visibe light

  • infrared

  • ultraviolet

  • microwave


27.

Velocity of electromagnetic waves in a medium depends upon

  • thermal properties of medium

  • mechanical and electrical properties of medium

  • electrical and magnetic properties of the medium

  • mechanical and magnetic properties of the medium


28.

In the electromagnetic spectrum, the visible spectrum lies between

  • radiowaves and microwaves

  • infrared and ultraviolet rays

  • microwaves and infrared spectrum

  • X-ray and γ-ray spectrum


Advertisement
29.

Maxwell in his famous equation of electromagnetism introduced the concept

  • AC current

  • DC current

  • displacement current

  • impedance


30.

Out of the following electromagnetic radiations, which has the shortest wavelength ?

  • Radiowaves

  • Infrared

  • X-rays

  • Visible light


Advertisement