JEE Mains · Physics · STD 12 - Electromagnetic waves
- JEE Mains 2022
- Medium
- MCQ
The electric field in an electromagnetic wave is given by \(E =56.5 \sin \omega( t - x / c ) \;NC ^{-1}\). Find the intensity of the wave if it is propagating along \(x-\)axis in the free space. (Given \(\left.\varepsilon_{0}=8.85 \times 10^{-12} \;C ^{2} N ^{-1} m ^{-2}\right)\)
Pick an option to check your answer.
Answer & Solution
Correct Answer
(B) \(4.24 \;Wm ^{-2}\)
Step-by-step Solution
Detailed explanation
\(I =\frac{1}{2} \varepsilon_{0} E _{0}^{2} c\)
\(I =\frac{1}{2} \times\left(8.85 \times 10^{-12}\right)(56.5)^{2} \times\left(3 \times 10^{8}\right)\)
\(=4.24 Wm ^{-2} .\)
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