At a particular time, The wave function contains all the information about the particle. It is not an observable quantity. But it does not have any physical significance. However, the square of the absolute value of the wave function has a physical significance. We will find |\u03c8(x,t)|2<\/sup> as a probability density. Probability density is a probability per unit length or we can say probability of finding the particle at a time t at position x.<\/p>\n\n\n\n The wave function \u03c8 associated with a moving particle is a complex quantity. We know the representation of complex wave function.<\/p>\n\n\n\n \u03c8(x, y, z, t<\/em>) = a<\/em> + ib<\/em><\/p>\n\n\n\n and its complex conjugate is<\/p>\n\n\n\n \u03c8*(x, y, z, t<\/em>) = a<\/em> \u2013 ib<\/em>.<\/p>\n\n\n\n The product of wave function and its complex conjugate is<\/p>\n\n\n\n \u03c8(x, y, z, t<\/em>)\u03c8*(x, y, z, t<\/em>) = (a<\/em> + ib<\/em>) (a<\/em> \u2013 ib<\/em>) = a<\/em>2<\/sup> + b<\/em>2<\/sup><\/p>\n\n\n\n a<\/em>2<\/sup> + b<\/em>2<\/sup> is a real quantity. <\/p>\n\n\n\n However, this can represent the probability density of locating the particle at a point in a given instant of time. <\/p>\n\n\n\n The positive square root of \u03c8(x, y, z, t<\/em>) \u03c8*(x, y, z, t<\/em>) is represented as |\u03c8(x, y, z, t<\/em>)|, called the modulus of \u03c8. The quantity |\u03c8(x, y, z, t<\/em>)|2<\/sup> is called the probability. However, the product of a complex number with its complex conjugate is a real and non-negative number. Hence, this interpretation is possible.<\/p>\n\n\n\n