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A wire is uniformly stretched to make its area of cross-section 1/nᵗʰ times (n > 0). What will be its new resistance (A) 1/n² times (B) n² times (C) 1/n times (D) n times |
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Answer» udent,◆ Answer -(B) n² TIMES ● Explanation -Before STRETCHING, specific resistance of wire is -ρ = RA/lEven after stretching, volume of STRETCHED wire will remain same.V = V'l.A = l'.A'l.A = l'.A/nl' = l.nResistance of new wire will be -R' = ρ.l'/A'R' = (RA/l) × (l.n) / (A/n)R' = R.n²Therefore, new resistance of the wire will n² times of old one.Hope that's all... |
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