Physics - Electromagnetic Waves

Question - 1

What is the progation velocity of an electromagnetic wave in a medium for which relative permittivity, \({ \epsilon }_{ r }\) = 3.1, and relative permeability, \({ \mu }_{ r }\) = 200 ?

  • A 3.0 \(\times\) 1010 ms-1 
  • B 1.20 \(\times\) 107 ms-1 
  • C 3.60 \(\times\) 107 ms-1 
  • D 1.5 \(\times\) 108 ms-1 

Question - 2

A broadcasting station transmits radio waves of wavelength 300 m. What is the inductance of an inductor that could be connected with a 2.40-\(\mu\)F capacitor to be in resonance with these waves?

  • A 3.3 \(\times\) 10-2 H
  • B 3.3 \(\times\) 10-8 H
  • C 3.3 \(\times\) 10-5 H
  • D 1.04 \(\times\) 10-8 H

Question - 3

A viberating electric charge radiates

  • A electric waves
  • B magnetic waves
  • C both (a) and (b)
  • D light waves

Question - 4

In an electromagnetic wave, light vector is

  • A electric vector
  • B magnetic vector
  • C electromagnetic vector

Question - 5

For electomagnetic waves propagating along x-axis, the wave must have the components

  • A (Ex, Hy)
  • B (Ey, Ez)
  • C (Ey, Hy)
  • D (Hy, Ez)

Question - 6

Which is NOT a part of electromagnetic spectrum?

  • A Beta rays
  • B Gamma rays
  • C Wireless waves
  • D T. V. waves

Question - 7

Rate of change of displacement vector has the dimension of

  • A charge per unit area
  • B current
  • C current per unit area
  • D charge

Question - 8

Choose INCORRECT statement :

  • A Optics is the branet of electromagnetism
  • B The speed of electomagnetic waves depends only on electric and magnetic properties of the medium they travel in, and not on the amplitudes of field variations.
  • C Displacement current is NOT a current in the real sense.
  • D Without displacement current, the electromagnetic radiation would have been possible.

Question - 9

Choose INCORRECT statement :

  • A A light wais charcterised by its electric vector \(\overset { \rightarrow }{ E } \), although it has a magnetic vector \(\overset { \rightarrow }{ H } \).
  • B It is the electric field vector which is responsible for all optical phenomena.
  • C Displacement current and conduction crrent in an electric circuit may not be continuous but their sum is always continuous.
  • D Displacement current is due to rate of flow charge between plates of a capacitor.

Question - 10

A  T.V. transmission tower has a height of 200 m. By how much should the height be increased to double its covering range?

  • A 400 m
  • B 600 m
  • C 800 m
  • D 300 m
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