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The velocity of electromagnetic radiatio...

The velocity of electromagnetic radiation in a medium of permittivity `epsilon_(0)` and permeability `mu_(0)` is given by:

A

`sqrt(epsilon_(0)/(mu_(0))`

B

`sqrt(mu_(0)epsilon_(0))`

C

`(1)/sqrt(mu_(0)epsilon_(0))`

D

`sqrt(mu_(0)/(epsilon_(0))`

Text Solution

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The correct Answer is:
To find the expression for the velocity of electromagnetic radiation in a medium characterized by permittivity \( \epsilon_0 \) and permeability \( \mu_0 \), we can follow these steps: ### Step-by-Step Solution: 1. **Understand the Relationship**: The velocity \( v \) of electromagnetic waves in a medium is related to its permittivity \( \epsilon \) and permeability \( \mu \) by the formula: \[ v = \frac{1}{\sqrt{\mu \epsilon}} \] 2. **Substitute the Values**: For free space, we have: - Permittivity \( \epsilon_0 = 8.85 \times 10^{-12} \, \text{F/m} \) (Farads per meter) - Permeability \( \mu_0 = 4\pi \times 10^{-7} \, \text{H/m} \) (Henries per meter) 3. **Calculate \( \mu_0 \epsilon_0 \)**: We need to multiply \( \mu_0 \) and \( \epsilon_0 \): \[ \mu_0 \epsilon_0 = (4\pi \times 10^{-7}) \times (8.85 \times 10^{-12}) \] 4. **Perform the Multiplication**: - Calculate \( 4\pi \approx 12.566 \) - Then multiply: \[ \mu_0 \epsilon_0 \approx 12.566 \times 10^{-7} \times 8.85 \times 10^{-12} \approx 1.112 \times 10^{-18} \] 5. **Find the Velocity**: Now, substitute back into the velocity formula: \[ v = \frac{1}{\sqrt{\mu_0 \epsilon_0}} = \frac{1}{\sqrt{1.112 \times 10^{-18}}} \] 6. **Calculate \( v \)**: \[ v \approx 3 \times 10^8 \, \text{m/s} \] 7. **Conclusion**: The speed of electromagnetic radiation in a vacuum (or free space) is approximately \( 3 \times 10^8 \, \text{m/s} \). ### Final Expression: Thus, the velocity of electromagnetic radiation in a medium characterized by permittivity \( \epsilon_0 \) and permeability \( \mu_0 \) is given by: \[ v = \frac{1}{\sqrt{\mu_0 \epsilon_0}} \approx 3 \times 10^8 \, \text{m/s} \]
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