Out of the following options which one can be used to produce a propagating electromagnetic wave?
1. A stationary charge
2. A chargeless particle
3. An accelerating charge
4. A charge moving at constant velocity
The energy of the EM wave is of the order of 15 KeV. To which part of the spectrum does it belong?
2. Infrared rays
3. Ultraviolet rays
The condition under which a microwave oven heats up a food item containing water molecules most efficiently in
1. the frequency of the microwave must match the resonant frequency of the water molecules
2. the frequency of the microwave has no relation with the natural frequency of water molecules
3. microwave are heatwaves, so always produce heating
4. infrared waves produce heating in a microwave oven
The electric field associated with an electromagnetic wave in vacuum is given by E= 40coswhere E, z, and t are in volt/m, meter, and second respectively. The value of wave vector k is:
3. 4. 3
The ratio of the amplitude of the magnetic field to the amplitude of electric field for an electromagnetic wave propagating in vacuum
is equal to
(a) the speed of light in vacuum
(b) reciprocal of speed of light in vacuum
(c) the ratio of magnetic permeability to the
electric susceptibility of vacuum
The electric and the magnetic field, associated with an electromagnetic wave, propagating along the +z-axis, can be represented by
The decreasing order of the wavelength of infrared, microwave, ultraviolet and gamma rays is
(a) gamma rays, ultraviolet, infrared, microwaves
(b) microwaves, gamma rays, infrared, ultraviolet
(c) infrared, microwave, ultraviolet, gamma rays
(d) microwave, infrared, ultraviolet, gamma rays
Which of the following statements is false for the properties of electromagnetic waves?
1. Both electric and magnetic field vectors attain the maxima and minima at the same place and the same time
2. The energy in an electromagnetic wave is divided equally between electric and magnetic vectors
3. Both electric and magnetic field vectors are parallel to each other and perpendicular to the direction of propagation of the wave
4. These waves do not require any material medium for propagation
The electric field of an electromagnetic wave in free space is given by where t and x are in seconds and meters respectively. It can be inferred that
(1) The wavelength is 188.4 m.
(2) The wave number k is 0.33 rad/m.
(3) The wave amplitude is 10 V/m.
(4) The wave is propagating along +x direction
Which one of the following pairs of statements is correct?
1. (3) and (4) 2. (1) and (2)
3. (2) and (3) 4. (1) and (3)
The velocity of electromagnetic radiation in a medium of permittivity and permeability is given by