Q151 / 160 · AP EAMCET 2004 · Physics
$n$ conducting wires of same dimensions but having restivities $1,2,3, . . n$ are connected in series. The equivalent resistivity of the combination is
- Correct answerA$1 \frac{n(n+1)}{2}$
- B$\frac{n+1}{2}$
- C$\frac{n+2}{2 n}$
- D$\frac{2 n}{n+1}$
Solution
Resistivity of the combination
$$
\begin{aligned}
=(1+2+3+\ldots+n)
=\frac{n(n+1)}{2}
\end{aligned}
$$
Hence, the correct answer is option: 'A'.