A : The poynting vector given as `bar(S) = (bar(E ) xx bar( B))/(mu_0)` represents the instantaneous intensity at a point.
R : The velocity of an electromagnetic wave is in the direction of the vector `bar( E) xx bar (B)`.

If bar(a) is a unit vector then bar(a)xx{bar(a)xx(bar(a)xxbar(b))}

If bar(a) is a unit vector then bar(a)xx{bar(a)xx(bar(a)xxbar(b))=

Three vectors bar(P) bar(Q) and bar(R) are shown in the figure.Let S be any point on the vector bar(R) .The distance between the points P and S is b|bar(R)| .The general relation among vectors bar(P) bar(Q) and bar(s) is

Three vectors bar(P) bar(Q) and bar(R) are shown in the figure.Let S be any point on the vector bar(R) .The distance between the points P and S is b|bar(R)| .The general relation among vectors bar(P) bar(Q) and bar(S) is qquad Y

If |bar(a) xx bar(b)|= bar(a).bar(b) , then find the angle between the vectors bar(a) and bar(b) .

If |bar(a).bar(b)| = |bar(a) xx bar(b)| & bar(a). bar(b) lt 0 , then find the angle between bar(a) and bar(b) .

Let bar(a), bar(b), bar(c ) be unit vectors, suppose that bar(a). bar(b) = bar(a). bar(c )= 0 and the angle between bar(b) and bar(c ) is pi//6 then show that bar(a)= +-2 (bar(b) xx bar( c))