Hello, in today's class we are going to discuss few things about electric dipole. So we always know that electric dipole is nothing but which consists of two charges, okay and it is opposite in magnitude and there is a something distance is there which is a less distance in between that, that becomes electric dipole. So we have lot of molecules maybe HCl, maybe hydrogen fluoride like that other molecules are there which are those are nothing but dipoles acts as if like a dipole only, okay positive charge and negative charge. Now always there is a question why that electric dipole moment is in always in the direction of negative to positive, okay so that is a question. So I am going to discuss, I am going to tell you mathematically why and how that electric dipole moment is always negative to positive. Now dipole moment is nothing but it is a vector quantity, we will denote in the letter of p which is equal to any charge the magnitude of any charge and the distance between them and the distance between the two charges. Now why it is always negative to positive that we have to check right. So two scenarios I am going to take, so case one I am going to take and case two I am going to take. In that we are not going to consider the dipole in x, y, z direction so though we are going to consider x, y, z, okay so I am going to consider the dipolear in this distance, the distance between them is 2A, okay and say this is minus Q, this is plus Q, this distance is x. Now let us consider the total dipole moment of this system, okay with respect to the origin, how I can write down the total dipole moment is nothing but the vectorial sum, okay, which is equal to the moment of a negative charge with respect to this plus the moment of positive charge with respect to this, this is 2A plus X. So, which direction it is? I, which direction it is? In x direction, no? Okay. So, now we can write down that minus QX minus plus 2AQ plus X into Q all are in EI direction. So, this is the scancels. I can write down 2AQ in x direction. So, x direction if you see means positive x direction. So, positive direction in this method it is negative to positive. Dipole moment is negative to positive charge. Meanwhile, go through this. So, another scenario that is X, Z and Y. So, at the first what I have kept here, the negative charge I have kept here. Now, I am going to take positive charge, negative charge this way. 2A is the distance, X is the distance. So, total moment of I can calculate. Total moment I can calculate is QX in x direction minus 2A plus X because the minus charge 2A plus XQI. So, if you substitute means QXI cap minus 2AQ minus Q minus XQI. So, I. So, what happens? The scancels you are going to get minus 2AQI cap or else you can write down 2AQ minus I cap. So, what is minus I cap? Minus I cap means negative to or in opposite direction of the x axis. That is negative to positive. So, hence we will conclude that the dipole moment is always negative charge minus Q2 plus Q. This is the mathematical expression. So, this is what today we have discussed. Kindly subscribe and like the videos. Thank you.