Question

An electromagnetic wave is travelling in vertically upward direction. At an instant, its electric field vector points in west direction. In which direction does the magnetic field vector point at that instant?

Answer 1

Given: Wave propagation (k) travelling in vertically upward direction (+x).

The electric field (E) vector points in the west direction (−x).

To Find: Magnetic field (B) direction

Using the right-hand rule:

`vec k = vec E xx vec B`

Point fingers of your right hand in the direction of the electric field E (West, −x).

Curl your fingers toward the direction of magnetic field B (to be determined).

Your thumb should point in the direction of wave propagation (upward, +2).

To satisfy this condition, B must point south (−y).