JEE Mains · Physics · STD 12 - 3. current electricity
Space between two concentric conducting spheres of radii \(a\) and \(b (b > a)\) is filled with \(a\) medium of resistivity \(\rho \). The resistance between the two spheres will be
- A \(\frac{\rho }{{2\pi }}\left( {\frac{1}{a}\,+\,\frac{1}{b}} \right)\)
- B \(\frac{\rho }{{2\pi }}\left( {\frac{1}{a}\,-\,\frac{1}{b}} \right)\)
- C \(\frac{\rho }{{4\pi }}\left( {\frac{1}{a}\,+\,\frac{1}{b}} \right)\)
- D \(\frac{\rho }{{4\pi }}\left( {\frac{1}{a}\,-\,\frac{1}{b}} \right)\)
Answer & Solution
Correct Answer
(D) \(\frac{\rho }{{4\pi }}\left( {\frac{1}{a}\,-\,\frac{1}{b}} \right)\)
Step-by-step Solution
Detailed explanation
\(R = \int\limits_a^b {\frac{{\rho {\rm{d}}x}}{{4\pi {x^2}}}} \) \(=\frac{\rho}{4 \pi}\left(\frac{1}{a}-\frac{1}{b}\right) \)
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