[sixthformer]

here's the experiment

yout have a fixed current, change the length of a wire, and measure the voltage. you then use this to work out the umm...resistance

what systematic errors could be made, and what random errors could be made?

[Manitude]

If you're using a mains supply then perhaps a power surge could happen, that would be random.

I suppose a systematic error would be if you didn't have a voltmeter with infinite resistance then all of your results would be slightly incorrect (unless of course you knew what the resistance was and accounted for it)

[sixthformer]

.ok ty any more ?

[JJ_in_the_fridge]

Wire isn't of constant cross sectional area. Voltmeter not calibrated correctly. Human error. Temperature of wire could increase.

This is your AS phys coursework right?

[sixthformer]

(Original post by JJ_in_the_fridge)
Wire isn't of constant cross sectional area. Voltmeter not calibrated correctly. Human error. Temperature of wire could increase.

This is your AS phys coursework right?

"Wire isn't of constant cross sectional area. Voltmeter not calibrated correctly. Human error. Temperature of wire could increase"

would those be systematic or random?

ty

do you do AQA physics?

this is practise for the ISA.

[chrisibailey]

first, did you get my pm? id really like some help :P
and in answer to your question:
a systematic error is where all of your results are shifted from the true value due to a consistent error. In your experiment your ammeter/voltmeter may not have read zero at the start (which you should have checked by attaching the voltmeter to itself) which would have caused all of your results to be a bit out. also you could have made a consistent error in technique which may have been poor technique in reading the length of the wire.

A random error is caused by poor technique/faulty instruments/human error leading to a few measurements being wrong, creating anomalies. this could happen if you sometimes read the length of the wire wrong/rounded it wrong or if you didnt keep variables the same,the wire may have gained in temperature.

[Cora Lindsay]

(Original post by sixthformer)
change the length of a wire

Measuring the length incorrectly would be an example of systematic error. How do you know the current you assume is actually correct? Is your voltmeter correctly calibrated? Thise wiuld be systematic errors too.

[sixthformer]

(Original post by Cora Lindsay)
Measuring the length incorrectly would be an example of systematic error. How do you know the current you assume is actually correct? Is your voltmeter correctly calibrated? Thise wiuld be systematic errors too.

would temperature be a systematic or random error/

[Cora Lindsay]

(Original post by sixthformer)
would temperature be a systematic or random error/

Well there will be both error types associated with T.

If you measure T itself, your measurement may be subject to both systematic error (incorrect reading, calibration etc) and random error (limitations of the measuring technique).

T may also be an indirect cause of systematic error, for example if the resistance changes significantly with temperature and you don't take account of the effect, or if the dimensions change as a result of heating. However, the reality is that these effects are likely to be so small in your experiment that you can neglect them.

You can work this sort of stuff out for yourself- a systematic error is a cock up, an incorrect reading, while a random error is the uncertainty inherent in making the measurement.

For example in a watch which records seconds, the random error will be of the order of a second, but in a watch which doesn't record seconds, the random error will be of the order of a minute. What's important is that the random error should be small in comparison with the quantity you are trying to measure. So you'd need a watch with seconds to measure 20 or 30 seconds;one with minutes only would be fine if you were measuring 40 or 50 minutes.

[sixthformer]

(Original post by Cora Lindsay)
Well there will be both error types associated with T.

If you measure T itself, your measurement may be subject to both systematic error (incorrect reading, calibration etc) and random error (limitations of the measuring technique).

T may also be an indirect cause of systematic error, for example if the resistance changes significantly with temperature and you don't take account of the effect, or if the dimensions change as a result of heating. However, the reality is that these effects are likely to be so small in your experiment that you can neglect them.

You can work this sort of stuff out for yourself- a systematic error is a cock up, an incorrect reading, while a random error is the uncertainty inherent in making the measurement.

For example in a watch which records seconds, the random error will be of the order of a second, but in a watch which doesn't record seconds, the random error will be of the order of a minute. What's important is that the random error should be small in comparison with the quantity you are trying to measure. So you'd need a watch with seconds to measure 20 or 30 seconds;one with minutes only would be fine if you were measuring 40 or 50 minutes.

ty

any more input people?

[sandeep0767]

is the paper on TSR ???

[georgiemuc]

Hey, can someone please explain what would be a random error and a systematic error when using a micrometer and what would you do to reduce the error in both cases.

Thanks

[Better]

bump