Question

The electric field of a plane electromagnetic wave travelling in +ve z-direction is described by ______.

Options

• `"E"_x = "E"_0 sin ("kz")`

• `"E"_x = "E"_0 sin ("kz" - omega"t")`

• `"E"_x = "E"_0 sin ("kz" + omega"t")`

• `"E"_x = "E"_0 sin (2"kz")`

Answer 1

The electric field of a plane electromagnetic wave travelling in +ve z-direction is described by `underline("E"_x = "E"_0 sin ("kz" - omega"t"))`.

Explanation:

Both electric and magnetic fields are perpendicular to the wave propagation direction in em-wave. The electric field should be perpendicular to the x-axis because the wave is travelling along it. It is provided by `"E"_x = "E"_0 sin ("kz" - omega"t")`, where k is the propogation constant and `omega` is the angluar velocity.