Graph Q from EK Verbal Reasoning + Math book

[qazwsxedc]

On page 16 of the EK VR and Math book (edition 6), question#3 asks which of the following graphs shows the relationship between frequency and wavelength through a vacuum( C = FW).

I thought the answer was B, where there is an inverse proportional relationship between frequency and wavelength. However, EK picked D, where there is y = 1/x^n type of relationship. I don't understand why this is correct, and why I am wrong. Why is the relationship inverse exponential and not inverse proportional?

B) \

D) \__ (supposed to look exponential lol)

On question# 5, it was same question except for P = W/t, in which case they picked a direct proportional relationship between P and W (answer = /). This to me is obvious and makes sense, but why is this relationship not the opposite the one above (C = WF). Ie P is proportional to W, versus F is inversely proportional to W ??

Any help would be appreciated. Thanks.

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[kobe200LATE]

Choice B is wrong because this graph would represent the relationship between frequency and wavelength if their sum was constant. This would be the correct graph is c = wavelength + frequency, not c = wavelength * frequency.

Choice is a better choice because when the product (as opposed to the sum) is constant, the graph is represented by choice D.

 

[kobe200LATE]

Also, the reason why #3 and #5 are different is because they aren't asking you to plot c vs. wavelength in #3 like they are asking you to plot Power vs. time in #5.

They are asking you to plot wavelength vs. frequency, which are not directly proportional