Find the resistance of a cube of edge $60 \mathrm{~cm}$, made of a material of specific resistance $60…

Find the resistance of a cube of edge $60 \mathrm{~cm}$, made of a material of specific resistance $60 \times 10^{-8} \Omega \mathrm{m}$.
  1. $2.5 \times 10^{-5} \Omega$
  2. $10^{-8} \Omega$
  3. $10^{-6} \Omega$
  4. $5 \times 10^{-4} \Omega$

Solution

Given, side of cube, $l=60 \mathrm{~cm}$ $ =60 \times 10^{-2} \mathrm{~m} $ Resistivity, $\rho=60 \times 10^{-8} \Omega-\mathrm{m}$ $\because$ Resistance, $R=\frac{\rho l}{A}$ $ \begin{aligned} \therefore \quad & =60 \times 10^{-8} \times \frac{60 \times 10^{-2}}{\left(60 \times 10^{-2}\right)^2} \\ & =10^{-6} \Omega \end{aligned} $

Asked in: AP EAMCET 2021 (23 Aug Shift 1)

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