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Reading Irradiance from a light meter

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Original post by Sataris
Yes, it sounds like you have verified the inverse square law

Thank you, I greatly appreciate it. I did two experiments, but my second set of results is harder to do a line of best fit with. the majority of them are relatively in a straight line but its the last three points of greater distance that make it look like a curve. What should I do?
(edited 5 years ago)
Original post by ottersandseals1
Thank you, I greatly appreciate it. I did two experiments, but my second set of results is harder to do a line of best fit with. the majority of them are relatively in a straight line but its the last three points of greater distance that make it look like a curve. What should I do?

If there is something quite obviously wrong with those last three data points then discount them and just fit the others instead. If they're only a bit off, fit the whole dataset as usual. In either case, try to come up with a justification for why those three points might be bad in your discussion/conclusion.
Original post by Sataris
If there is something quite obviously wrong with those last three data points then discount them and just fit the others instead. If they're only a bit off, fit the whole dataset as usual. In either case, try to come up with a justification for why those three points might be bad in your discussion/conclusion.

But either way definitely do a line of best fit? Also I've seen textbooks refer to light radiation, is that just light?
(edited 5 years ago)
Original post by ottersandseals1
But either way definitely do a line of best fit?

Oh yeah, it's just up to you whether you include those three points or not
Original post by Sataris
Oh yeah, it's just up to you whether you include those three points or not

Also I've seen textbooks refer to light radiation, is that just light whether natural or artificial?
Original post by ottersandseals1
Also I've seen textbooks refer to light radiation, is that just light whether natural or artificial?

Yep, light is light
Original post by Sataris
If there is something quite obviously wrong with those last three data points then discount them and just fit the others instead. If they're only a bit off, fit the whole dataset as usual. In either case, try to come up with a justification for why those three points might be bad in your discussion/conclusion.

I have just realised quite a lot of the points are producing a curve, still line of best fit even though it may pass through very little points?
Original post by ottersandseals1
I have just realised quite a lot of the points are producing a curve, still line of best fit even though it may pass through very little points?

Go spec ops on that ****
Original post by Sataris
Go spec ops on that ****

Should I just plot a couple of points instead?
Original post by ottersandseals1
Should I just plot a couple of points instead?

Plot all of it
Original post by Sataris
Plot all of it

If there is graph of current against distance. Can I relate the current to irradiance and say they are the same thing?
Original post by ottersandseals1
If there is graph of current against distance. Can I relate the current to irradiance and say they are the same thing?

What is this current?
Original post by Sataris
What is this current?

I found a graph of current against distance and was curious if that related to irradiance.
Original post by ottersandseals1
I found a graph of current against distance and was curious if that related to irradiance.

But, current of what?
Original post by Sataris
But, current of what?

On the website it doesn't say. Its current over distance and the line is sloping like an ordinary graph of irradiance against distance
Original post by ottersandseals1
On the website it doesn't say. Its current over distance and the line is sloping like an ordinary graph of irradiance against distance

Maybe it's talking about attentuation over distance? But that is generally an exponential decay
Original post by Sataris
Plot all of it

If I plot the first 10 points I get draw a line of best fit but if I draw all the points I get a curve, what should I do?
Original post by ottersandseals1
If I plot the first 10 points I get draw a line of best fit but if I draw all the points I get a curve, what should I do?

I told you, you have to make a judgment on whether those points are actually outliers or not. If they aren't, plot all of them
Original post by Sataris
I told you, you have to make a judgment on whether those points are actually outliers or not. If they aren't, plot all of them

Can I plot all of them and ignore them them in my line of best fit?
Original post by ottersandseals1
Can I plot all of them and ignore them them in my line of best fit?

Yes, just explain what you've done in the writeup

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