AP EAMCET · PHYSICS · Electromagnetic Waves
The average value of electric energy density in an electromagnetic wave is.
[where \(\mathrm{E}_0\) is peak value]
- A \(\frac{\epsilon_0 \mathrm{E}_{\mathrm{rms}}^2}{4}\)
- B \(\frac{1}{2} \epsilon_0 \mathrm{E}_0^2\)
- C \(\frac{1}{2} \epsilon_0 \mathrm{E}_0\)
- D \(\frac{1}{4} \epsilon_0 \mathrm{E}_0^2\)
Answer & Solution
Correct Answer
(D) \(\frac{1}{4} \epsilon_0 \mathrm{E}_0^2\)
Step-by-step Solution
Detailed explanation
The energy density in EM wave is \(\mathrm{u}=\frac{1}{2} \varepsilon_{\mathrm{o}} \mathrm{E}^2=\frac{1}{2} \varepsilon_{\mathrm{o}} \mathrm{E}_0^2 \sin ^2(\omega \mathrm{t}-\mathrm{kx})\) \(\therefore \quad\) Average energy density,…
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