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2 Physics AS Wave Questions

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Why bother with a post grad? Are they even worth it? Have your say! 26-10-2016
1. Hiya, thanks for your time I have two questions in which the mark schemes are of no help explaining how to understand these, so can I please have some help?
(I've reworded the questions slightly to put them into context)

Q1) A standing wave has been set up with a microwave transmitter emitting a microwave onto a metal sheet. Why is the minima detected with the probe near the metal sheet much smaller than the ones near the speaker?

Q2)

Many thanks for your time

Max
2. Q1) The amplitude of the wave attenuates with distance. Therefore, as the wave moves towards the sheet and is reflected back, its amplitude is very gradually reducing. So, when the reflected part combines with the outgoing signal produced at the transmitter, the amplitude of the reflected part is smaller than the amplitude of the newly emitted wave. When the two are added together, the minima will not be quite zero. However, at the metal sheet the incident waveform and the reflected waveform will have pretty much the same amplitude and will almost completely cancel each other out at the minima.

Q2) As the wavefronts approach the beach, their speed decreases. However, as the frequency remains the same this means that the wavelength reduces so the wavefronts will become closer together. Also, as the waves are incident at an angle to the shore refraction will cause some bending of the wavefronts as the waves in the shallower parts will move slower than those in the deeper waters. See this page for some help http://www.coastal.udel.edu/ngs/waves.html
3. (Original post by Teenie2)
Q1) The amplitude of the wave attenuates with distance. Therefore, as the wave moves towards the sheet and is reflected back, its amplitude is very gradually reducing. So, when the reflected part combines with the outgoing signal produced at the transmitter, the amplitude of the reflected part is smaller than the amplitude of the newly emitted wave. When the two are added together, the minima will not be quite zero. However, at the metal sheet the incident waveform and the reflected waveform will have pretty much the same amplitude and will almost completely cancel each other out at the minima.

Q2) As the wavefronts approach the beach, their speed decreases. However, as the frequency remains the same this means that the wavelength reduces so the wavefronts will become closer together. Also, as the waves are incident at an angle to the shore refraction will cause some bending of the wavefronts as the waves in the shallower parts will move slower than those in the deeper waters. See this page for some help http://www.coastal.udelT.edu/ngs/waves.html
Thank you so so much!!!

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