brazil-enem 2021 Q109

brazil-enem · Other · enem__day2 Not Maths
Scientists from the University of New South Wales, in Australia, demonstrated in 2012 that Ohm's Law is valid even for very thin wires, whose cross-sectional area comprises only a few atoms. The table presents the areas and lengths of some of the constructed wires (respectively with the same units of measurement). Consider that resistivity remains constant for all geometries (an approximation confirmed by the study).
AreaLengthElectrical resistance
Wire 19312R1
Wire 2447R2
Wire 3254R3
Wire 41106R4

The electrical resistances of the wires, in increasing order, are
(A) $\mathrm{R}1 < \mathrm{R}2 < \mathrm{R}3 < \mathrm{R}4$.
(B) $\mathrm{R}2 < \mathrm{R}1 < \mathrm{R}3 < \mathrm{R}4$.
(C) $\mathrm{R}2 < \mathrm{R}3 < \mathrm{R}1 < \mathrm{R}4$.
(D) $\mathrm{R}4 < \mathrm{R}1 < \mathrm{R}3 < \mathrm{R}2$.
(E) $\mathrm{R}4 < \mathrm{R}3 < \mathrm{R}2 < \mathrm{R}1$.
Scientists from the University of New South Wales, in Australia, demonstrated in 2012 that Ohm's Law is valid even for very thin wires, whose cross-sectional area comprises only a few atoms. The table presents the areas and lengths of some of the constructed wires (respectively with the same units of measurement). Consider that resistivity remains constant for all geometries (an approximation confirmed by the study).

\begin{center}
\begin{tabular}{|l|l|l|l|}
\hline
 & Area & Length & Electrical resistance \\
\hline
Wire 1 & 9 & 312 & R1 \\
\hline
Wire 2 & 4 & 47 & R2 \\
\hline
Wire 3 & 2 & 54 & R3 \\
\hline
Wire 4 & 1 & 106 & R4 \\
\hline
\end{tabular}
\end{center}

The electrical resistances of the wires, in increasing order, are

(A) $\mathrm{R}1 < \mathrm{R}2 < \mathrm{R}3 < \mathrm{R}4$.\\
(B) $\mathrm{R}2 < \mathrm{R}1 < \mathrm{R}3 < \mathrm{R}4$.\\
(C) $\mathrm{R}2 < \mathrm{R}3 < \mathrm{R}1 < \mathrm{R}4$.\\
(D) $\mathrm{R}4 < \mathrm{R}1 < \mathrm{R}3 < \mathrm{R}2$.\\
(E) $\mathrm{R}4 < \mathrm{R}3 < \mathrm{R}2 < \mathrm{R}1$.