MCQ
A plane electromagnetic wave with a single frequency moves in vacuum in the positive $x$ direction. Its amplitude is uniform over the $yz$ plane its wavelength:
- AIncrease
- BDecrease
- ✓Same
- DNone
✓
Answer
Correct option: C.
Same
The same amount of energy passes through equal areas parallel to the $yz$ plane as the wave travels in the $+x$ direction, so the amplitude and the intensity, which is proportional to the square of the amplitude, do not change.
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