JEE Main & Advanced Sample Paper JEE Main Sample Paper-7

  • question_answer
    The \[I-V\] characteristic of a conductor at two different temperatures \[{{T}_{1}}\] and \[{{T}_{2}}\] are shown below. The difference in temperature is proportional to

    A)  \[\tan \theta \]                               

    B)  \[\cot \theta \]

    C)  \[\cot 2\theta \]                             

    D)  \[\sin 2\theta \]

    Correct Answer: C

    Solution :

    Slope at \[{{T}_{2}}>\] Slope at \[{{T}_{1}}\]. So \[{{R}_{2}}<{{R}_{1}}\]. \[{{R}_{2}}={{R}_{0}}(1+\alpha {{T}_{2}})\] \[{{R}_{1}}={{R}_{0}}(1+\alpha {{T}_{1}})\] Subtracting, we get, \[{{R}_{0}}\alpha ({{T}_{2}}-{{T}_{1}})={{R}_{2}}-{{R}_{1}}\] \[{{T}_{2}}-{{T}_{1}}=\cot ({{90}^{0}}-\theta )-\cot \theta \] \[=\tan \theta -\cot \theta \] \[{{T}_{2}}-{{T}_{1}}=\frac{{{\sin }^{2}}\theta -{{\cos }^{2}}\theta }{\sin \theta \cos \theta }=\frac{-2\cos 2\theta }{\sin 2\theta }\] or \[{{T}_{1}}-{{T}_{2}}=2\,\cot \,2\theta \]


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