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InterviewSolution
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Explain linearly polarized waves and give it definition. |
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Answer» Solution :Consider holding a long STRING that is hel horizontally, the other end of which is to b FIXED. If we move the end of the string up and dowi in a periodic manner. A wave is generate propagating in the + x-direction as shown in figure (a).  The curves represent the displacement of a string at t = 0 and at `t=Deltat` respectively when this sinusoidal wave is propagating in the + x direction. This is shown in figure (a). In figure (b) the curve represents the time variation of the displacement at x = 0 when a sinusoidal wave is propagating in the + xdirection.  The displacement of the wave in the + xdirection OCCURS in the y-direction so its equation, `y(x,t)=asin(kx-omegat)` where a = amplitude of wave `omega=2piv` angular FREQUENCY of wave `k=(2pi)/(lamda)` wave vector and `lamda=(2pi)/(k)` WAVELENGTH According to this equation the displacement of particle of string (in y-direction) is at right angles to the direction of propagation of the wave, so it is known as a transverse wave. Here displacement is in the y-direction so it is called y-polarised wave. Since each point on the string moves on a straight line, so this wave is called a linearly polarised wave. The string always remains confined to the xyplane and therefore it is called as a plane polarised wave. If we can consider the vibration of the string in the xz-plane generating a 2-polarised wave whose displacement will be z(x,t) `=asin(kx-omegat)`. This is also the linearly polarised wave and it is transverse wave. |
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