maturk Posted September 11, 2015 Report Share Posted September 11, 2015 Yooooo! So I'm super confused, y'all get this question? The answer is supposed to be B. It's from May 2003 both SL and HL paper 1s question 16. If anyone understands, could you explain? Thanks in advance! Cheers! Reply Link to post Share on other sites More sharing options...
Vioh Posted September 11, 2015 Report Share Posted September 11, 2015 Yooooo! So I'm super confused, y'all get this question? The answer is supposed to be B. It's from May 2003 both SL and HL paper 1s question 16. If anyone understands, could you explain? Thanks in advance! Cheers! Well obviously the first step is to take a look at this formula . According to the picture shown in the question, the wavelength () is clearly , and you should be able to convince yourself that that is true. Now, you might think that is the frequency, but that's not the case because the question only mentions that "the number of crests passing through the log per unit time is ". In fact, this implies that the frequency must be . This can be understood if you realize that the frequency is the number of wavelengths passing through per second, and that a wavelength is the distance between two consecutive wave-crests. I've illustrated this with a diagram down below. You can see that the wave-crests are represented by the solid lines, while the wave-lengths are represented by the space spanned by the dotted lines. So for wave-crests, the corresponding number of wavelengths is . So the speed is 1 Reply Link to post Share on other sites More sharing options...
maturk Posted September 12, 2015 Author Report Share Posted September 12, 2015 Whoa! Thanks so much I understand it completely now. Reply Link to post Share on other sites More sharing options...
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