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InterviewSolution
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A steel wire of length 20 cm and uniform cross-sectional area of `1 mm^(2)` is tied rigidly at both the ends at `45^(@)C`. If the temperature of the wire is decreased to `20^(@)C`, then the change in the tension of the wire will be [Y for steel `= 2 xx 10^(11 Nm^(-2)`, the coefficient of linear expansion for steel `= 1.1 xx 10^(-5)//.^(@)CC^(-1)`]A. 22 NB. 32 NC. 55 ND. 60 N |
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Answer» Correct Answer - c Coefficient of linear expansion `alpha = (dL)/(L(Delta T))` `:. (Delta L)/(L) = alpha Delta T` and `Y = (F.L)/(A.Delta L)` From Eq. 1 `F = YA (Delta L)/(L) = YA alpha Delta T` `:. F = 2 xx 10^(11) xx 1 xx 10^(-6) xx 1.1 xx 10^(-5) xx 25` `:. F = 55 N` |
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