 This is Dr. Rupali Sherke from Waltzing Institute of Technology, Sholapur working as an associate professor in electronics department. In this video lecture, we are going to discuss with the wave polarization. Learning outcomes at the end of this session students are able to define what is wave polarization and also they can see the different types of the wave polarization. As we know that the wave is nothing but a it consists of a or it is associated with the electric field and the magnetic field. So, here we are seeing the behaviour of the electric field in this case to define a wave polarization. Therefore, we define a polarization of the wave is referred to the time varying behaviour of the electric field strength vector at some fixed point in the space or we can also called as a polarization is a property of the wave that describe the orientation of their oscillations. It is necessary to study the polarization because it has a significant in the areas of science and technology that deals with the wave propagation such as in optics, in telecommunications and radar and seismology. Let us see what are the different types of the polarization. Polarization is defined in the three different types that is linear polarization, elliptical polarization and circular polarization. Let us discuss one by one. In a linear polarization, the wave is said to be linearly polarized if it is electric field the magnitude of the electric field vector is stressed along the either in a horizontal direction or in a vertical direction. For that let us consider a wave travelling in a z direction and it is having the electric field in a x direction and in y direction means its electric field components are present. The resultant e is given by e will be equal to e x a x bar plus e y a y bar. Based on this we have defined the two types of polarization that is horizontally linear polarization and vertical linear polarization. Let us see what is horizontal and vertical polarization. For horizontal polarization we consider a wave which is having only its x components electric field components that is in a x direction and that the electric field components in a y direction is equal to 0. Then the wave is said to be linearly polarized in x direction. If you observe in this animated film and limited ppt it is shows that the electric field are stressed along the horizontal line and this is a wave equation for the same. The wave is said to be vertically polarized if its e y components are not equal to 0 means they are present and its e x components are equal to 0 and this is a wave equation and this diagram we see that the resultant e are traced along the vertical that is along the y axis. The next is a elliptical polarized. The wave is said to be elliptical polarized if its electric field components in a x and y direction are neither in phase nor they are having the same amplitude. Then the resultant e will traces the focus of points that will form a ellipse therefore, the wave is said to be elliptical polarized. Now, let us see with the equation. Now, let us consider the electric electric vector in a x direction as a a sin omega t that is a wave in a a sin omega t where a is representing its amplitude and it is a time varying signal and electric components in a y direction is minus b cos omega t where minus b is an amplitude in a y direction amplitude of the signals in a y direction. If we combine these two equations by squaring the two equations first and then we combine then we get the e x square by a square plus e y square plus b square which is equal to sin square omega t plus cos square omega t. If we reduce the equation then sin square omega t plus cos square omega t is equal to 1 that is why this equation is nothing but the equation of the ellipse. So, if it in this diagram it shows that the two waves in a x and y direction are stressing the point which is forming the ellipse. Circular polarization if e x and e y have a exactly same amplitude that is b is equal to a or a is equal to b and are exactly 90 degree out of phase that is electrical component e x components and y components are out of phase by 90 degree exactly then the resultant e will form a circle and the wave is said to be a circularly polarized. Now, let us consider the same equations which we are considered previously in place of b we substitute it as a because we are considering the amplitude with the same value. Same way we square the two equations and add them the common term is a square it will be sin square a square sin square omega t plus minus a square sin square omega t again a square sin square omega t plus cos square omega t will be equal to 1 it only remains with a e square x plus e y square will be equal to a square this is nothing but a equation with the equation of the circle with radius a. Now, the circular polarization is being stress in a two form one in the right hand circular polarization and left hand circular polarization in for a right hand circular polarization the phase difference between the electric field along the x and y directions up exactly equal to minus 90 degree then the wave is said to be right hand circularly polarized. We can observe in this figure that the tracing of the point is in a circular form for the left hand circular polarization the wave electric field in a x and y directions are with the same amplitude but phase of that angle is positive 90 degree then the wave is said to be right hand polarizing same thing it is also stressing the circle. Now, I pause the video and identify the polarization of the wave given by these two equation here two components in a of the x that is e x in a x direction and e y in a y direction if you observe these two equation the amplitudes are different thing then what could be the which type of polarization it will be the magnitude of the e y and e x components are not same thus it cannot be a circular polarized and the phase difference is equal to 0 that is why it is a linearly polarized. These are the few references.