Electromagnetic Waves Practice Test

The speed of electromagnetic waves in vaccum is equal to

A plane electromagnetic wave of frequency 20 MHz travels through a space along x-direction. If the electric field vector at a certain point in space is 6 Vm⁻¹, then what is the magnetic field vector at that point?

In electromagnetic spectrum, the frequencies of γ-rays and x-rays and ultraviolet rays are denoted by n₁,n₂ and n₃ respectively, then

The electromagnetic waves detected using a thermopile and used in physical therapy are

The condition under which a microwave oven heats up a food item containing water molecules most efficiently is

The velocity of electromagnetic radiation in a medium of permittivity ε₀ and permeability μ₀ is given by

If c is the velocity of light in free space, the time taken by light to travel a distance x in a medium refractive index μ is

The electric field part of an electromagnetic wave in a medium is represented by Ex = 0
Ey = 2.5 (N / C) cos [(2π x 10⁶ rad/m) t – (π x 10⁻² rad/s) x ];
Ez = 0. The wave is:

which of the following statement is false for the properties of electromagnetic waves?

The electric and magnetic field associated with an E.M. wave, propagating along the +z axis, can be represented by

The decreasing order of wavelength of infrared, microwave, ultraviolet and gamma rays is

The electric field associated with an e.m. wave in vacuum is given by E = i 40 cos (kz – 6 x 10⁸ t), where E, z and t are in volt/m, meter and seconds respectively. The value of wave vector k is:

The ratio of amplitude of magnetic field to the amplitude of electric field for an electromagnetic wave propagating in vacuum is equal to:

An electromagnetic wave of frequency v = 3.0 MHz passes from vacuum into a dielectric medium with relative permittivity ε = 4.0. Then

Which radiations are used in tratement of muscles ache?