**8. Define Radiation Intensity. What is it’s significance?**

Radiation Intensity in given direction is defined as the power per unit solid angle in that direction.

• The power radiated per unit area in any direction is given by pointing vector P.

• For distant field for which E and H are orthogonal in a plane normal to the radius vector, E2 The power flow per unit area is given by P = watts/sqm

• There are r 2 square meters of surface area per unit solid angle( or steradian).

•The radiation intensity gives the variation in radiated power versus position around the antenna. We can find the total power radiated by the antenna by integrating the Poynting vector over the surface of a sphere that encloses the antenna. This is equivalent to integrating the radiation intensity over a unit sphere.