A wire of length L and cross-sectional 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.

5 answers

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
Consider a c-Si 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?
(It's very urgent, therefore we kindly ask you to forward this email to your CEO. Thanks)

Dear CEO,

This email is from China domain name registration center, which mainly deal with the domain name registration in China. On 20-08-2020, we received an application from Hongxin Ltd requested "jiskha" as their internet keyword and China (CN) domain names (jiskha.cn, jiskha.com.cn, jiskha.net.cn, jiskha.org.cn). But after checking it, we find this name conflict with your company name or trademark. In order to deal with this matter better, it's necessary to send this message to your company and confirm whether this company is your distributor or business partner in China?

Best Regards
Oliver Liu | Service & Operations Manager
China Registry (Head Office)
www.chinaregistry.com.cn
Tel: +86-02161918696
Fax: +86-02161918697
Mob: +86-13816428671
6012, Xingdi Building, No. 1698 Yishan Road, Shanghai 201103, China