POYNTING VECTOR

SYLLABUS OF ARYABHATTA  KNOWLEDGE UNIVERSITY, PATNA, BIHAR, INDIA

BRANCH : MECHANICAL ENGINEERING

 MODULE 7: ELECTROMAGNETIC WAVES

THE WAVE EQUATION; PLANE ELECTROMAGNETIC WAVES IN VACUUM, THEIR TRANSVERSE NATURE AND POLARIZATION; RELATION BETWEEN ELECTRIC AND MAGNETIC FIELDS OF AN ELECTROMAGNETIC WAVE; ENERGY CARRIED BY ELECTROMAGNETIC WAVES AND EXAMPLES. MOMENTUM CARRIED BY ELECTROMAGNETIC WAVES AND RESULTANT PRESSURE. REFLECTION AND TRANSMISSION OF ELECTROMAGNETIC WAVES FROM A NON-CONDUCTING MEDIUM-VACUUM INTERFACE FOR NORMAL INCIDENCE.

Poynting Vector

The energy carrying capacity of an electromagnetic wave is expressed by the cross product of vector E and H and denoted by letter S is called Poynting Vector. i.e

The direction of energy flow at any point is normal to both E and H vectors.

Poynting vector represents the energy transfer by an electromagnetic wave per unit area per unit time. The SI unit of the Poynting vector is the watt per square metre (W/m²). It is named after its discoverer John Henry Poynting who first derived it in 1884.