Question

An electromagnetic wave travelling in free space has a magnetic field amplitude of $6 \times 10^{-4} \, T$. The amplitude of its electric field is:

• A. $1.8 \times 10^5 \, V/m$
• B. $1.8 \times 10^4 \, V/m$
• C. $6 \times 10^4 \, V/m$
• D. $6 \times 10^5 \, V/m$

Answer 1

Answer: (A)

$1.8 \times 10^5 \, V/m$

Answer 2

The relationship between the amplitude of the electric field ($E_0$) and the amplitude of the magnetic field ($B_0$) for an electromagnetic wave traveling in free space is given by $E_0 = c B_0$, where $c$ is the speed of light in free space ($c \approx 3 \times 10^8 \, m/s$).

Given: $B_0 = 6 \times 10^{-4} \, T$ $c = 3 \times 10^8 \, m/s$

Calculation: $E_0 = (3 \times 10^8 \, m/s) \times (6 \times 10^{-4} \, T)$ $E_0 = 18 \times 10^{4} \, V/m$ $E_0 = 1.8 \times 10^5 \, V/m$