When 5V potential difference is applied across a wire of length 0.1m, the drift speed of electrons is 2.5×10−4ms−1 . If the electron density in the wire is 8×1028m−3 , the resistivity of the material is close to:
Held on 4 Apr 2015 · Verified 6 Jul 2026.
1.56×10−5Ωm
1.6×10−8Ωm
1.6×10−7Ωm
1.6×10−6Ωm
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A short bar magnet placed with its axis at $30^{\circ}$ with an external field of 800 Gauss, experiences a torque of $0.016 \mathrm{~N}. \mathrm{m}$. The work done in moving it from most stable to most unstable position is $\alpha \times 10^{-3} \mathrm{~J}$. The value of $\alpha$ is $\_\_\_\_$.
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