Edexcel PHYSICS Doubts

[Dangerous99]

How would you calculate % uncertainty. I know its the first thing u answered in the topic but its not working with this question
They give us 2 values 18.66 and 18.64 and ask us to find the percentage uncertainty.

[Malak]

How would you calculate % uncertainty. I know its the first thing u answered in the topic but its not working with this question
They give us 2 values 18.66 and 18.64 and ask us to find the percentage uncertainty.

Is there anything else in the question? :S like original reading, instrument mentioned or something

[Nobody]

which question? the one i answered?

[Dangerous99]

Is there anything else in the question? :S like original reading, instrument mentioned or something

the values are the time taken for 20 oscillation per second, and they give us the mean time for one oscillation which is 0.932 seconds.

[Dangerous99]

which question? the one i answered?

no not the exact same question. I meant this ones percentage uncertainty as well

[Deadly_king]

June 2010, Q2v

Why do we multiply them both with 2? :S

This is because you made two readings before calculating the answer. I've not read the question but am pretty sure there was something like initial and final readings.

Since two readings were made, same uncertainty was carried out twice. That's why we multiply it by two

Hope it helps

[Romeesa-Chan]

How would you calculate % uncertainty. I know its the first thing u answered in the topic but its not working with this question
They give us 2 values 18.66 and 18.64 and ask us to find the percentage uncertainty.

Percentage uncertainty = uncertainty/mean value x 100%

[Dangerous99]

Percentage uncertainty = uncertainty/mean value x 100%

yea they did something like that in the mark scheme, they did (0.5/18.64) x 100%
I really dont get where they got the 0.5 from tho

[studz]

yea they did something like that in the mark scheme, they did (0.5/18.64) x 100%
I really dont get where they got the 0.5 from tho

even i dint get where did they bring 0.5 from

anyway guys can you list out the uncertainties of measurement of the following apparatus?
1. metre rule
2. voltmeter (not digital)
3. ammeter (not digital)
4. voltmeter (digital)
5. ammeter (digital)
6. Digital stopwatch
by the way, is human error an uncertainty too? Is human error 0.01s?
If it is, then please consider this case:
when a ball is allowed to free fall for 2s, the distance is recorded. (different sizes of ball are used) the distance has an uncertainty, however the uncertainty is human error (0.01s+0.01s) or uncertainty of the metre rule (0.5mm+0.5mm)?

thanks 

[Nobody]

0.5 is the uncertainty.
sometimes it's what YOU HAVE to remember or figure it out yourself.
it's easy
want me to help you out there?

[studz]

0.5 is the uncertainty.
sometimes it's what YOU HAVE to remember or figure it out yourself.
it's easy
want me to help you out there?

yes please moderator help  :$

[Romeesa-Chan]

This is because you made two readings before calculating the answer. I've not read the question but am pretty sure there was something like initial and final readings.

Since two readings were made, same uncertainty was carried out twice. That's why we multiply it by two

Hope it helps

Thank you very much! XD

[Dangerous99]

0.5 is the uncertainty.
sometimes it's what YOU HAVE to remember or figure it out yourself.
it's easy
want me to help you out there?

Yes please! how do u figure that out?
they also wrote "change in 20T= 0.5 - 1.0 s [reaction time] leading to correct %"
what reaction time?!

[Nobody]

even i dint get where did they bring 0.5 from

anyway guys can you list out the uncertainties of measurement of the following apparatus?
1. metre rule
2. voltmeter (not digital)
3. ammeter (not digital)
4. voltmeter (digital)
5. ammeter (digital)
6. Digital stopwatch
by the way, is human error an uncertainty too? Is human error 0.01s?
If it is, then please consider this case:
when a ball is allowed to free fall for 2s, the distance is recorded. (different sizes of ball are used) the distance has an uncertainty, however the uncertainty is human error (0.01s+0.01s) or uncertainty of the metre rule (0.5mm+0.5mm)?

thanks 

okay, to all those who've got trouble with uncertainty.

Uncertainty of ANY instrument is the SMALLEST readable value of it.

in a metre rule
like this one

the smallest readable value is 1 mm.

so the uncertainty is 1 mm for this ruler.

[Dangerous99]

okay, to all those who've got trouble with uncertainty.

Uncertainty of ANY instrument is the SMALLEST readable value of it.

in a metre rule
like this one

the smallest readable value is 1 mm.

so the uncertainty is 1 mm for this ruler.

then shouldnt the uncertainty be 0.01 because the values they give are 18.66 and 18.46 they can only read it upto 0.01?
sorry By the way im just panicking here thats y im pressing on it so much