Physics!! Help!!!!!
posted by Melissa on .
A wire of length L and crosssectional area A has resistance R. What will be the resistance R_stretched of the wire if it is stretched to twice its original length? Assume that the density and resistivity of the material do not change when the wire is stretched.
Express your answer in terms of the wire's original resistance R.

The product L*A remains constant after stretching. If L doubles, A decreases by 1/2
Resistance is proportional to L/A.
R2/R1 = L2/L1 *A1/A2 = 4
R1 is the original resistance and R2 is the final resistance. 
A)becomes double B)remains same C)becomes half C)becomes square

Remain same

Consider a cSi solar cell whose fingers have a resistance R=0.1 Ohm. What would be the finger's resistance (in Ohm) if the finger's width is doubled and the finger's height is one third of its initial value?