For resistors in parallel, the total resistance $R$ is given by $1/R = 1/R_1 + 1/R_2$. The resistance of a wire is $R = \rho L/A$, where $\rho$ is resistivity, $L$ is length, and $A$ is cross- sectional area.
Two resistors $R_1$ and $R_2$ arranged in parallel combination in an electrical closed circuit are made of the same material and of same thickness. If the length of $R_2$ is twice the length of $R_1$, then the total resistance $R$ satisfies
Asked in UPSC NDA 1 2022 · Topic: Electric Current (Factors affecting resistance (length, area, material, temperature))
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