is anyone good at physics that could help me out?

Question

sorry im crap at this
if you were to send a flow of electrons down a wire and measure its resistance then change the lengh of the wire what would happen?
will the relationship be a proportianal relationship like if you double the lengh will resistance double or triple or something
sorry its unclear
thankyouxxx

Answer 1

R=k L/A
R - resistance
k - material constant
L - length of the wire
A - area of the wire's cross section.

Increase the length and resistance will increase
Increase th cross sectional area and resistance will decrees.

Answer 2

Yes!

A wire has a set resistance per metre. If you double the length, you will double it's resistance, three times the length is three times the resistance and so on. It's a nice linear relationship.

The only thing is that this does not apply with the thickness though. (Since it has to do with the cross-sectional area of the wire and if you think of maths, the area of a circle is Pi x R^2). So halving the diameter of the wire, actually makes it a lot thinner and so a lot higher resistance.

That's the only catch - the thickness!

I hope this helps?!

Answer 3

Hello,

(ANS) YES! If you send a stream of electrons along a wire of a fixed or known length. You can measure the resistence in the wire and it can give you a factor of say X.

**If you change the length of the same quality wire then you change the amount of resistence.

**Therefore if you were two double or triple the previous fixed length then yes! the amount of resistance increases in portion to the length.

Rule of thumb principal says increased line length = increased resistence. i.e. the longer the wire the greater the resistence.

**ALL of this applies of course to telecoms & braodband itself.

**Thus for example the braodband signal & therefore the upload & download speeds are dependant upon the both line length, & noise levels (measured in decibels Db). So if your house is very close to the BT phone exchange you'll probably see very fast speeds on downlaods say 7megs. But conversley if you live 3kilometers away you may only get 1-2megs and thats down to line length & noise levels on the line.

IR

Answer 4

You are right! Resistance is proportional to the length of the resistor.
It may help to consider an analogy that is a bit easier (and safer) to experience than electricity. Use a plastic straw to drink something thick like a milkshake. Slurp as hard as you can for one second and think about how much milkshake that came into your mouth. Now, cut the straw in half (not lengthwise!) and slurp for 1 second. How much milkshake this time? Is it about double? It should be because liquid flowing through a pipe follows a similar principle to electrons flowing through a metal wire.
Enjoy the rest of your milkshake!

Answer 5

Yes, the resistance will double.

Resistors add in series, so stringing two identical wires together one after the other gives you twice the resistance of just one wire. Make sense?

Edit: Resistance does NOT go up with the diameter. It goes down like the diameter squared (or cross sectional area). Remember that resisters in parallel add up in a funny inverse way, so that two resistors in parallel have half the resistance.

Answer 6

Also depends on how hot the wire becomes. hotter the wire, the more resistance there is as the particles in the wire have more kinetic energy adn therefore move more. This means that the electrons are blocked frm flowing

Answer 7

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Answer 8

length and diameter both adjust resistance in a linear fashion.