Turn on thread page Beta
 You are Here: Home >< Physics

Physics AS Qualitative assessment! watch

1. Hi! What would be the reasons for the calculated values of the resistance differing to the experimental values of the resistance across lamps in series and parallel?
2. (Original post by Awesomesauce)
Hi! What would be the reasons for the calculated values of the resistance differing to the experimental values of the resistance across lamps in series and parallel?
Some off the top of my head:

(1) Resistance of wires - in calculations you usually assume it to be zero. However, I have to admit to have no clue how much this could affect the actual values.

(2) As the current flows, bulb's temperature rises and so does its resistance. It stabilises only when it has reached temperature high enough. Also, bulb's resistance changes over time as it is used (so that a new and an identical used bulb have different resistances).

(3) Measurement uncertainties - the measured value is not the true value. The only thing you know is that very probably the true value lies within the range of two uncertainties (but not necessarily always does so).
3. (Original post by jaroc)
Some off the top of my head:

(1) Resistance of wires - in calculations you usually assume it to be zero. However, I have to admit to have no clue how much this could affect the actual values.

(2) As the current flows, bulb's temperature rises and so does its resistance. It stabilises only when it has reached temperature high enough. Also, bulb's resistance changes over time as it is used (so that a new and an identical used bulb have different resistances).

(3) Measurement uncertainties - the measured value is not the true value. The only thing you know is that very probably the true value lies within the range of two uncertainties (but not necessarily always does so).
Damn. Should have read this yesterday. Just done my practical today and only wrote down that point. Thanks for your help anyway though! I am extremely extremely jealouse of your offers for physics. UCL is my dream uni.
4. (Original post by Awesomesauce)
Damn. Should have read this yesterday. Just done my practical today and only wrote down that point. Thanks for your help anyway though! I am extremely extremely jealouse of your offers for physics. UCL is my dream uni.
I hope that you did well despite mentioning just one point.

As for the offers, all the problem now is meeting the conditions I don't know whether you're applying this year or next, but I do wish you all the best
5. (Original post by jaroc)
I hope that you did well despite mentioning just one point.

As for the offers, all the problem now is meeting the conditions I don't know whether you're applying this year or next, but I do wish you all the best
Same to you! I'm sure you will get into Oxford (The city of dreaming spires.... ). I wrote down more than one point, but only one from your list. Anyway; I doubt I will get into UCL. I'm in AS and recently got back my first set of results in Chem, physics and maths c1. I got a a b. The b in the easiest maths module C1, so things are not looking too good for an AAA uni.

Turn on thread page Beta

Related university courses

TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

This forum is supported by:
Updated: March 17, 2011
Today on TSR

Edexcel GCSE Maths Unofficial Markscheme

Find out how you've done here

AQA Maths Paper 1 exam discussion

Poll

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE