Chemical Forums
Chemistry Forums for Students => Undergraduate General Chemistry Forum => Topic started by: mana on April 04, 2021, 03:11:31 AM
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hi guys
what is the exact relationship between cycles per second and Hertz? if they are the same, can you explain why this picture says the opposition, and how it has calculated the cycles per second?
thanks in advance for your help
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That is wrong. Where you get this.
1 cycle per sec. Is equal 1 Hertz.
https://en.m.wikipedia.org/wiki/Cycle_per_second
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It's wrong because they (whoever made the figure) are counting "zero" as the first cycle. But that's not how cycles work.
Consider the top left figure, where it says 4 cycles per second = 3 hz. Yes, the wave has four crests in the defined time period, but the first one doesn't count as a cycle. A cycle is when you go from one crest to the next. There are only three cycles in that figure (indicated as λ1), not four as specified.
Imagine it this way. Let's say you exit your house and walk around your block repeatedly for exactly one hour. During the hour you pass your house twice and arrive back at your house exactly at the hour point. In total you were at your hour four times during the hour (the initial one, passing twice, and at the end), but you only made three cycles around the block. Just coming out of the door is not a cycle. A cycle is starting at your door, going all the way around, and arriving back at the starting point.
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Well spotted. But after that they lose even the ability to count. ν2 would be 7 "cycles" on that wrong definition, and ν3 13. They seem to be assuming that "cycles" are directly proportional to frequency (which is true when properly defined).
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I didn't even look at the two below the first one - you're right. Really weird. Wonder where this came from.