Speed of EM Wave in Free Space – Rankers Physics

Properties of EM Waves: Practice Problem & Solution

Speed of EM wave in free space is given by (where symbols have their usual meaning)
\( c = \frac{\varepsilon_0}{\mu_0} \)
\( c = \sqrt{\mu_0 \varepsilon_0} \)
\( c = \frac{1}{\sqrt{\mu_0 \varepsilon_0}} \)
\( c = \sqrt{\frac{\mu_0}{\varepsilon_0}} \)

Solution Explained:

To solve this problem, we apply the core principles of Properties of EM Waves. Understanding the underlying formula is key to arriving at the correct answer below:

From Maxwell's electromagnetic theory, the speed of light \( c \) in vacuum is determined by the electric permittivity \( \varepsilon_0 \) and magnetic permeability \( \mu_0 \) of free space through the relation \( c = \frac{1}{\sqrt{\mu_0 \varepsilon_0}} \).

Leave a Reply

Your email address will not be published. Required fields are marked *

Similar Practice Questions

Explore conceptually related problems to test your knowledge.

1. For a plane EM wave propagating in x-direction, which one of the following combination gives the correct possible directions for electric field (\(\vec{E}\) ) and magnetic field (\(\vec{B}\) ) respectively?
2. Assertion (A): An E.M. wave has constantly interchanging electric and magnetic fields, which are perpendicular to each other. Reason (R): The direction of propagation is given by \((\vec{B} \times \vec{E})\).  
3. Which of the following electromagnetic radiations have the smaller wavelength? (1994)
4. Modified ampere circuital law is given by (symbols have their usual meaning)
5. Match List-I with List-II \[ \begin{array}{ll@{\hspace{2cm}}ll} \textbf{List-I (Electromagnetic waves)} & \textbf{List-II (Wavelength)} \\[0.5em] \text{a. AM radio waves} & \text{(i) } 10^{-10}\text{ m} \\ \text{b. Microwaves} & \text{(ii) } 10^2\text{ m} \\ \text{c. Infra-red radiations} & \text{(iii) } 10^{-2}\text{ m} \\ \text{d. X-rays} & \text{(iv) } 10^{-4}\text{ m} \end{array} \] Choose the correct answer from the options given below: (2022)