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Question
Two resistors A and B have resistances RA and RB, respectively, and RA < RB. The resistivities of their materials are ρA and ρB.
Options
ρA > ρB
ρA = ρB
ρA < ρB
The information is not sufficient to find the relation between ρA and ρB
Solution
The information is not sufficient to find the relation between ρA and ρB
The resistance R of a conductor depends on its resistivity ρ, length l and cross-sectional area A. Thus,
\[R = \rho\frac{l}{A}\]
From the given comparison of resistances, we cannot derive the correct relation between the resistances. We also need to know the cross-sectional areas and the lengths of both the conductors before concluding about their resistivities. Only then can the relation between the resistivities be found.
The information is not sufficient to find the relation between ρA and ρB.
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