Help with maths please (scientific notation)

[sam90]

Hi all just had this homework sent me for next weekend been about 10 years since I've messed with a scientific calculator I think I've got the basics right of how to calculate it but when I put it into the calculator it's not coming up with what I'm expecting I think I'm inputting something wrong ? As far as I'm aware this is how I'm calculating the question..
Q. Calculate the resistance of 100m of cooper conductor if the C.S.A is 1.5mm2 and the resistivity is taken as 17.5×10-9 ohms meters

So I'm thinking I should be doing

R=pl
A

17.5×10-9×100 / 1.5×10-6

Is this the correct formula or am I wrong before I start ?

Thanks all

 

[JAWS]

17.5x10-9 x 100 / 1.5x10-6 = 1.16. Yes you’re correct

R=pl
A

 

[The Ghost]

Hope this helps looks like yours is nearly right though. As to on the calculator now somewhere I think I have the working out to do that. Although I have seen a way of doing it that cancels out the top and bottom 10bar6 The only difference is that the resistivity of copper and aluminium are different and you would have to look that up.
Edit: looks like you have in fact!

 

[sam90]

Thanks guys think I've got it then .. I've got that book vortigern just needed it explaining from a person didn't click at first this is the anwser I've just got .. I'm guessing that's right then ..

 

[Richard Burns]

Your result is numerically 1.16 but it is x 10-12

It should be just ohms not 10-12 ohms.

For the calculator you want to input 6, ±, 10x , X, 1.5 = M+

9, ±, 10x, X, 17.5, =, X, 100, =, /, MR, =

I am not sure if the superscripts are going to come through but -12 and the x of 10x should be superscripts.

 

[happysteve]

If you're getting an answer 1.166666 x10^-12, it suggests you've got the top line correct, but you've divided by 1.5x10^6, rather than dividing by 1.5x10^-6 (i.e. you forgot the minus in the exponent).

 

[sam90]

Is that Right now then guys ?

 

[The Ghost]

What mode is your calculator in? I remember having to set the mode to get the correct answer. Looks like yours is in Deg mode which I can't remember if that is the correct one. Just ignore me if that is a complication too far.

 

[sam90]

What mode is your calculator in? I remember having to set the mode to get the correct answer. Looks like yours is in Deg mode which I can't remember if that is the correct one. Just ignore me if that is a complication too far.

To be honest mate I don't know our course was called off last weekend due to the snow so he sent us this for something to do and he said do as much research as you can and we will recap when we're all back in next week so we have all gone in a bit blind on this so I'll ask him about this on Saturday

Thanks

 

[ElectroChem]

Get yourself one of these mate, you'll find the display makes calculations like these much easier to enter.

 

[JAWS]

Are you at able skills Sam

Get yourself one of these mate, you'll find the display makes calculations like these much easier to enter.

Agreed these are superb. I paid £12 for mine from Tesco yet see them in there the other day for £9 something.

 

[sam90]

Are you at able skills Sam


Agreed these are superb. I paid £12 for mine from Tesco yet see them in there the other day for £9 something.

Hahah what's the odds of that I ordered one yesterday lol

 

[sam90]

Are you at able skills Sam


Agreed these are superb. I paid £12 for mine from Tesco yet see them in there the other day for £9 something.

No mate it's a small training centre local to me only 5 of us in the class