A Level Physics: Percentage Uncertainty Example Questions

Question 8 from the multiple choice of the 2018 OCR AS Physics Paper: Breadth in Physics;
Question 6 part c from the 2018 OCR AS Physics Depth in physics.
Music Credit: Digital Horizon from Microsoft Video Editor
Chapters:
00:00 Intro
00:35 Multiple Choice Question
03:46 Precise measurement
06:29 Resistivity and percentage uncertainty

[endrayt]

i don’t know if it’s because i’m a noob, but for literally the first question i did the same calculation as you but got 30% not 20%. 2x(.2/4x100+.3/3x100)

[im.Davidd]

Hi, thanks for this, I have an assessment coming up and I now fully understand uncertainties.

[jtcvhgn]

At 3:13 why didn't you close the brackets? Aren't up only multiply the 2 by the percentage uncertainty in The current?

[fatihachowdhury]

thank you so much for these videos sir. These are just so helpful AND also sir, you are literally the best physics teacher out here.✨

[kike-horr]

Hi, for the last question, why don't you do ( (0.01/0.12) / 2 ) x 2
because D is being divided by 2 and we must divide uncertainties by constants too, right?

[haniaashar]

11:15 how to know when to multiply and divide????

[puddleduck]

thank you so much!! I have a test on this tomorrow!

[ellisfletcher]

4:48 is it acceptable to say vernier calipers?

[stephanie]

At 5:43, I answered the question by saying a vernier capiler should be used - it the same as a micrometer?

[ozgebaskr]

Hi, thank you so much for these videos they are very helpful! I was wondering for the first question, my approach was finding half the range of I^2 which was 1.6 and after that I also squared 4 which was 16 so I had an uncertainty like 16 +- 1.6 . Finally I just calculated the percentage uncertainty for both 16 +- 1.6 and 3.0 +- 0.3 then added them and I still got 20%. Can this be an alternative solution? or was it just pure luck lol.

[amy]

Hi - i was just wondering why on the last question you do not divide by 2 on the diameter? Thank you

[kryptictrotium]

i have A question. for the last one, the area part of the formula, if we use r = 0.06 +- 0.01mm then r^2 % uncertainity would be 0.02 / 0.06 no?

[fatihachowdhury]

in the last question, the part of % uncertainty why do we not convert the units of d (diameter) from mm to m as L is in m too and we took r (radius) in m as well

[toriiramlall]

Hi there, I'm just a bit confused on the last question. Why do you multiply the uncertainty I'm the diameter by 2?

[archiesutherland]

when writing out the absolute and percentage uncertainty, should you match the number of decimal places as the answer or the significant figures?

[dash]

Why did you work out the percentage uncertainty in d squared in the last question?

[binodtharu]

What is the music playing in the background ?

[yanliliananz]

Hi, sir. I think you might made a mistake that the last page actually equal to 23%, is not 18%.

[tee]

Hi why didn't you say 2(0.1/0.06) since its (d/2)² why didn't we consider the over 2 for the percentage uncertainty