InterviewSolution
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InterviewSolution
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Resistance of tungsten wire at `150^(@)C` is `133 Omega`. Its resistance temperature coefficient is `0.0045//^(@)C`. The resistance of this wire at `500^(@)C` will be |
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Answer» Correct Answer - `215 Omega` Here, `R_(160) = 132 Omega R_(400) = ?` `alpha = 4.5 xx 10^(-3).^(@)C^(-1)` Now `R_(t) = R_(0)(1 + alpha t)` `:. R_(160) = R_(0) [1 + (4.5 xx 10^(-3))xx 100]` or `132 = R_(0)[1+4.5 xx 10^(-3)xx 100]`……(i) and `R_(400) = R_(0) [1 + 4.5 xx 10^(-3)xx400]`.....(ii) Dividing (ii) by (i) we get `(R_(400))/(132) = (1+ 4.5 xx 10^(-3) xx 400)/(1+ 4.5 xx 10^(-3) xx 400)` `= (1+ 1.80)/(1+ 0.72) = (2.80)/(1.72) = 1.63` `R_(400) = 132 xx 1.63 = 215 Omega` |
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