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Question: Answered & Verified by Expert
A plane electromagnetic wave of frequency \( 20 \mathrm{MHz} \) travels through a space along \( x \) direction.
If the electric field vector at a certain point in space is \( 6 \mathrm{~V} \mathrm{~m}^{-1} \), what is the magnetic field
vector at that point?
PhysicsMotion In One DimensionKCETKCET 2014
Options:
  • A \( 2 \times 10^{-8} \mathrm{~T} \)
  • B \( \frac{1}{2} \times 10^{-8} \mathrm{~T} \)
  • C 2T
  • D \( \frac{1}{2} T \)
Solution:
1076 Upvotes Verified Answer
The correct answer is: \( 2 \times 10^{-8} \mathrm{~T} \)
The electric field vector and magnetic field vector are related as
\[
\frac{E}{B}=c
\]
We know that \( c=3 \times 10^{8} \mathrm{~ms}^{-1} \) and it is given that \( E=6 \mathrm{Vm}^{-1} \) Therefore,
\( \frac{6}{B}=3 \times 10^{8} \Rightarrow B=\frac{6}{3 \times 10^{8}}=2 \times 10^{-8} \mathrm{~T} \)
Thus, magnetic field vector is \( 2 \times 10^{-8} \mathrm{~T} \).

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