Ground Wave Propagation

Sky Wave Propagation

Space Wave Propagation

The maximum range of ground or surface wave propagation depends on-

Define the term critical frequency in relation to sky wave propagation of electromagnetic waves.

A : Longitudinal waves do not exhibit the phenomenon of polarisation . R : In longitudinal waves medium particle vibrate in direction normal to the wave propagation .

Electromagnetic waves with frequency greater than the critical frequency of ionosphere cannot be used for communication using sky wave propagation, because:

A: When light travels from a rarer to a denser medium, it loses some speed but it doesn't imply a reduction in the energy carried by the light wave. R: Energy carried by a wave depends on the amplitude of the wave and not on the speed of wave propagation.

A wave is propagating along x-axis. The displacement of particles of the medium in z-direction at t=0 is given by : z= exp[-(x+2)^(2)] where 'x' is in meter. At t=1s, the same wave disturbance is given by z=exp[-(x-2)^(2)] . Then the wave propagation velocity is :-

Assertion: The electromagnetic waves of shorter wavelength can travel longer distances on earth's surface thane those of longer of longer wavelengths. Reason: Shorter the wavelength, the larger is the velocity of wave propagation. Also, shorter the wavelength, shorter is the velocity of wave propagation.

A standing wave propagating with velocity 300ms^(-1) in an open pipe of length 4 m has four nodes. The frequency of the wave is