# Resistance of a piece of metal

## Homework Statement

How does the resistance of a piece of metal change if both its length and its diameter are reduced to one half their original values?
It is increased to 4 times the original value
It doubles
It remains unchanged
It is halved
It is reduced to 1/4 of the original value

## Homework Equations

R = pL/A where P is the resistivity constant

## The Attempt at a Solution

I am not sure how to relate the area to change in area

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## The Attempt at a Solution

I am not sure how to relate the area to change in area
I think you can assume it's a round wire.

lightgrav
Homework Helper

they call one dimension a "diameter" , which becomes half
... how does the new Area compare to the old Area ?
(it's not about _change_ , it is about new = "some number" times old)

they call one dimension a "diameter" , which becomes half
... how does the new Area compare to the old Area ?
(it's not about _change_ , it is about new = "some number" times old)
Assume it's a round wire, with diameter d, the new diameter will be d/2.
old length is L, new length is 2L

Calculate old and new resistance, compare.