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7. Two wires of the same length and the same resistivityare connected in parallel. Find the ratio of their areas ofcross section if the ratio of their electrical resistancesis 4:3 |
Answer» <html><body><p>1:4</p><p></p><p>The resistance of a wire of length l and <a href="https://interviewquestions.tuteehub.com/tag/cross-939411" style="font-weight:bold;" target="_blank" title="Click to know more about CROSS">CROSS</a> section <a href="https://interviewquestions.tuteehub.com/tag/area-13372" style="font-weight:bold;" target="_blank" title="Click to know more about AREA">AREA</a> A is given by,</p><p>R=ρ(l/A).</p><p>So</p><p>R2R1=l2l1A1A2=14.</p><p>Now current through a wire is i ∝ 1/R.</p><p>∴i2i1 = R1R2 = 41</p><p>If their <a href="https://interviewquestions.tuteehub.com/tag/ends-971392" style="font-weight:bold;" target="_blank" title="Click to know more about ENDS">ENDS</a> have the same <a href="https://interviewquestions.tuteehub.com/tag/potential-1161228" style="font-weight:bold;" target="_blank" title="Click to know more about POTENTIAL">POTENTIAL</a> differences then currents through them</p><p>will be in the ratio of 1:4.</p><p></p><p></p></body></html> | |