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# AS Physics Homework Help!!!! URGENT before Thursday Watch

1. I am having trouble with some of my homework questions

what is the effect of contact resistance between the resistor and connecting clip on the values of current?

i think the answer is, The resistance is lowered and a increase in current because there is an increase in surface area so the current can pass through more easily,
but is this right?

the next question asks to explain the type of error?
i know its systematic but how do I explain it

Thank you for all your help
2. Contact resistance is exactly how it sounds - an extra bit of resistance brought about by the contact. So the total resistance in the circuit will increase therefore decreasing the current.

And yes, that is a systematic error because it is a problem within the equipment itself.

I hope this helps.
3. thank you that did help but didn't answer the question
so the resistance will be increased when crocodile clips are connected to the resistor
but why will they be increased
I thought because crocodile clips are wider they would allow more electrons through lowering resistance...
why is the resistance increased
4. The extra resistance comes from the actual contact. The current has to 'jump' from one material to the other. Surface areas is irrelevant - any connection generates a contact resistance.

I hope this makes things clearer.
5. thank you for your help i really appreciate it

Updated: April 18, 2012
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