AS Biology P34 Guesses

[redd]

Lol.. forgot to mention it! Its 0.5%

how 0.5 % ??

 

[Sheikh Nahiyan]

how 0.5% ??

oh dammit! I told you the wrong thing! Sorry!

Uncertainty of that ruler in the question is calculated like this: [+-0.5mm/10(0 to 1 has 10 divisions)] x 100 = 5%

So, you write your answer as + - 5%

 

[mrnt3250]

Least count of ruler: 0.1 cm = 1 mm
Minimum error (uncertainty) of ruler therefore is 0.1/2 = 0.05 cm or 0.5 mm
To find percentage uncertainty of the measurement taken by a ruler, depending on how many times u have taken a measurement, add the uncertainty (0.05) and divide the total uncertainty by the amount measured.

 

[redd]

Least count of ruler: 0.1 cm = 1 mm
Minimum error (uncertainty) of ruler therefore is 0.1/2 = 0.05 cm or 0.5 mm
To find percentage uncertainty of the measurement taken by a ruler, depending on how many times u have taken a measurement, add the uncertainty (0.05) and divide the total uncertainty by the amount measured.

minimum error is 0.1mm ..why the marking scheme says 1.0mm 0r 5 % ?? why not 0.5mm ??

 

[Ikram Khaliq]

minimum error is 0.1mm ..why the marking scheme says 1.0mm 0r 5 % ?? why not 0.5mm ??

because for scales, you take two readings and subtract them to get a measurement. hence, when compounded, the error becomes 0.5+0.5=1mm.

 

[redd]

because for scales, you take two readings and subtract them to get a measurement. hence, when compounded, the error becomes 0.5+0.5=1mm.

http://papers.xtremepapers.com/CIE/...nd AS Level/Biology (9700)/9700_s07_qp_31.pdf
Q#2 a(iii) they give +/- o.5mm in marking scheme ??? why ?

 

[Ikram Khaliq]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Biology (9700)/9700_s07_qp_31.pdf
Q#2 a(iii) they give +/- o.5mm in marking scheme ??? why ?

I'm sorry. I don't get the question. are we measuring the actual thickness using a microscope or the figure? What is the transparent ruler they are referring to?

 

[mrnt3250]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Biology (9700)/9700_s07_qp_31.pdf
Q#2 a(iii) they give +/- o.5mm in marking scheme ??? why ?

Maybe the least count of the ruler is different..
Cause it says use the transparent ruler, not your ruler. (still maybe wrong..)

 

[redd]

I'm sorry. I don't get the question. are we measuring the actual thickness using a microscope or the figure? What is the transparent ruler they are referring to?

is there any difference in the uncertainity in the ruler if we use it to measure figure or in the microscope ??

 

[redd]

Maybe the least count of the ruler is different..
Cause it says use the transparent ruler, not your ruler. (still maybe wrong..)

i dont think coz in another paper oct 07 ..they give the uncertainity in the ruler as 0.5mm ??
http://papers.xtremepapers.com/CIE/...nd AS Level/Biology (9700)/9700_w07_qp_32.pdf
Q#1 b(ii)

 

[Ikram Khaliq]

is there any difference in the uncertainity in the ruler if we use it to measure figure or in the microscope ??

How can we friggin' use a standard plastic ruler with a microscope? There must have been another 'transparent ruler' that they are talking about.

 

[Ikram Khaliq]

is there any difference in the uncertainity in the ruler if we use it to measure figure or in the microscope ??

How can we friggin' use a standard plastic ruler with a microscope? There must have been another 'transparent ruler' that they are talking about.

 

[redd]

How can we friggin' use a standard plastic ruler with a microscope? There must have been another 'transparent ruler' that they are talking about.

perhaps ! ...if we measure a figure with a mm ruler den wats da uncertanity ? o.5 mm or 1.0 ??

 

[mrnt3250]

That's what I also said, but according to common sense, you do as follows:
Find the least count of the measuring device you're using, half of the least count is the minimum (1 measurement) uncertainty of that device.
Leave the rest for CIE

 

[Ikram Khaliq]

arghh my head is spinning. :'(

 

[Ikram Khaliq]

perhaps ! ...if we measure a figure with a mm ruler den wats da uncertanity ? o.5 mm or 1.0 ??

Red, in measuring depth we can obviously not measure from the zero mark so there'll probably be an error at both ends. I don't know. Sorry.

 

[redd]

yea..i am thinking da same

 

[Dukeofwin]

So it'll probably be Stem or Root slides right?

 

[Dukeofwin]

Anyone please post a Paper which has question for comparison for 2 slides! Thanks

 

[joanna omar]

what was the ides of question 2 in bio 31 or 34 any idea ?