Em Waves Question 103
Question: Consider an electromagnetic wave propagating in vacuum. Choose the correct statement:
Options:
A) For an electromagnetic wave propagating in $ +y $ direction the electric field is $ \vec{E}=\frac{1}{\sqrt{2}}E _{0},(x,t),\hat{z} $ and the magnetic field is $ \overrightarrow{B}=\frac{1}{\sqrt{2}}B _{0}(x,t)\hat{y} $
B) For an electromagnetic wave propagating in $ +y $ direction the electric field is $ \vec{E}=\frac{1}{\sqrt{2}}E _{yz}(x,t),\hat{x} $ and the magnetic field is $ \vec{B}=\frac{1}{\sqrt{2}}B _{yz}(x,t),\hat{y} $
C) For an electromagnetic wave propagating in $ +x $ direction the electric field is $ \vec{E}=\frac{1}{\sqrt{2}}E _{0},(y,z,t) $ $ ( \hat{y}+\hat{z} ) $ and the magnetic field is $ \vec{B}=\frac{1}{\sqrt{2}}B _{0},(y,z,t),(\hat{y}+\hat{z}) $
D) For an electromagnetic wave propagating in $ +x $ direction the electric field is $ \vec{E}=\frac{1}{\sqrt{2}}E _{yz},(x,t),( \hat{y}-\hat{z} ) $ and the magnetic field is $ \vec{B}=\frac{1}{\sqrt{2}}B _{yz},(x,t),( \hat{y}-\hat{z} ) $
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Answer:
Correct Answer: D
Solution:
Wave in X-direction means E and B should be function of x and t. $ \overset{\scriptscriptstyle\frown}{y}-\overset{\scriptscriptstyle\frown}{z}\perp \overset{\scriptscriptstyle\frown}{y}+\overset{\scriptscriptstyle\frown}{z} $
BETA
