Question 16

The electric field in an electromagnetic wave is given by $$\vec{E} = \hat{i}40\cos\omega(t - z/c)\ NC^{-1}$$. The magnetic field induction of this wave is (in SI unit):

The electric field is $$\vec{E} = \hat{i}40\cos\omega(t - z/c)$$ NC⁻¹.

The wave propagates in the +z direction (from the argument $$t - z/c$$).

Direction of E: $$\hat{i}$$ (x-direction)

For EM wave: $$\vec{B} = \frac{\hat{k} \times \vec{E}}{c}$$ where $$\hat{k} = \hat{z}$$

$$\hat{z} \times \hat{i} = \hat{j}$$

$$\vec{B} = \hat{j}\frac{40}{c}\cos\omega(t - z/c)$$

The correct answer is Option 4.

Create a FREE account and get:

Download resources