A wire measures $40\text{ cm}$ in length and has a diameter of $2.0\text{ mm}$. It has a resistance of $0.30\,\Omega$. Which wire, made from the same material, has a resistance of $0.15\,\Omega$?
- Alength $20\text{ cm}$, diameter $1.0\text{ mm}$
- Blength $20\text{ cm}$, diameter $4.0\text{ mm}$
- Clength $80\text{ cm}$, diameter $1.0\text{ mm}$
- Dlength $80\text{ cm}$, diameter $4.0\text{ mm}$