A metallic wire of resistance R and resistivity ρ is cut into six equal parts. Now each part is stretched to six times its length. The new resistance and resistivity of each part will be, respectively: |
6 R and 6 ρ 36 R and 6 ρ 6 R and ρ R and ρ |
6 R and ρ |
The correct answer is Option (3) → 6 R and ρ Resistance of original wire (R) and Resistivity (ρ) $R_{part}$ (cut into 6 equal pieces) = $\frac{R}{6}$ Also, each part is stressed six times its length - $L_{new}=6×\frac{L}{6}=L$ $A_{new}=\frac{original\,volume}{New\,length}=\frac{A.\frac{L}{6}}{L}=\frac{A}{6}$ $R_{new}=ρ\frac{L}{A_{new}}=6$ $\frac{ρL}{A}=6R$ Also, Resistivity (ρ) is a material property and does not change with dimension. |