Question

The electromagnetic wave propagates in free space with a speed of:

• A. \( 1.9 \times 10^6 \) m/s
• B. \( 3 \times 10^8 \) m/s
• C. \( 2.12 \times 10^2 \) m/s
• D. \( 3.8 \times 10^4 \) m/s

Hint:

The speed of light in vacuum is a fundamental constant and is crucial for determining the speed of electromagnetic waves.

Answer 1

The Correct Option is B

Step 1: The speed of electromagnetic waves in free space is given by: \[ c = \frac{1}{\sqrt{\mu_0 \varepsilon_0}} \] where \( \mu_0 \) is the permeability of free space and \( \varepsilon_0 \) is the permittivity of free space. 
Step 2: Using known values: \[ \mu_0 = 4\pi \times 10^{-7} \text{ H/m}, \quad \varepsilon_0 = 8.854 \times 10^{-12} \text{ F/m} \] 
Step 3: Substituting into the equation: \[ c = \frac{1}{\sqrt{(4\pi \times 10^{-7}) (8.854 \times 10^{-12})}} \approx 3 \times 10^8 \, \text{m/s} \]