Em Waves Question 101
Question: An electromagnetic wave with frequency cd and wavelength $ \lambda $ travels in the $ +y $ direction. Its magnetic field is along + x-axis. The vector equation for the associated electric field (of amplitude $ E _{0} $ ) is
Options:
A) $ \overset{\to }{\mathop{E}},=-E _{0}\cos ( \omega t+\frac{2\pi }{\lambda }y )\hat{x} $
B) $ \overset{\to }{\mathop{E}},=E _{0}\cos ( \omega t-\frac{2\pi }{\lambda }y )\hat{x} $
C) $ \overset{\to }{\mathop{E}},=E _{0}\cos ( \omega t-\frac{2\pi }{\lambda }y )\hat{z} $
D) $ \overset{\to }{\mathop{E}},=-E _{0}\cos ( \omega t+\frac{2\pi }{\lambda }y )\hat{z} $
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Answer:
Correct Answer: C
Solution:
[c] In an electromagnetic wave electric field and magnetic field are perpendicular to the direction of propagation of wave. The vector equation for the electric field is $ \vec{E}=E _{0},\cos ,( \omega t-\frac{2\pi }{\lambda }y )\hat{z} $
BETA
