Question

a aluminum wire of unknown length has a diameter of 0.25 inch and resistance of 0.28 ohms. by several successive passes through drawing dies the diameter of the wire is reduce by 0.05inch. calculate the resistance of the reduced size wire.

Answer 1

Use formula: Resistance R = resistivity* length /area
Here, resistivity and length are not changed, so R is inversely proportional to area i.e radius ^2
Hope this helps.

Answer 2

\[R=\frac{ PL }{A ^2 } ? do i need \to compute for the CM=(D)^2\]

Answer 3

R = pl/pi*r^2, right ?

Answer 4

it doesnt need to convert inch to mil?

Answer 5

No

Answer 6

ok ...

Answer 7

there are two diameter ... 0.25-0.05? (inch) do it need to subtract?

Answer 8

no

Answer 9

Convert the diameters to radii. Tell me the radii.

Answer 10

No, radius is half of diameter.

Answer 11

is it 0.125

Answer 12

Right

Answer 13

so whats next?

Answer 14

how about the lenght?

Answer 15

shailkumar .. whats next?

Answer 16

Ok. As you know that p and l are not change, so pl is also not change i.e pl = constant call it k

Answer 17

So we have R = k/pi*r^2

Answer 18

Put r = 0.125 and R = 0.28 ohm and find k

Answer 19

Once you've got k, use R = k/pi*r^2 again, put r = 0.05 and the value of k you got.This will give you R

Answer 20

K= 0.0137?

Answer 21

Right

Answer 22

R= 1.74433 ohms?

Answer 23

Yes

Answer 24

that's the final answer?

Answer 25

What do you think? What else is left?

Answer 26

none.. THANK YOU SO MUCH