RAJASTHAN PMT Rajasthan - PMT Solved Paper-2006

  • question_answer
    If resistance of wire at \[50{}^\circ C\] is \[5R\,\Omega \] and at \[100{}^\circ C\] is \[6R\,\Omega .\] find resistance of \[0{}^\circ C\] :

    A)  \[0R\,\,\Omega \]                                         

    B)         \[2R\,\,\Omega \]

    C)         \[3R\,\,\Omega \]                                         

    D)         \[4R\,\,\Omega \]

    Correct Answer: D

    Solution :

                    \[{{R}_{t}}={{R}_{0}}(1+\alpha \,\,\Delta t)\]                 \[5R={{R}_{0}}(1+\alpha \times 50)\]                      ... (i) and        \[6R={{R}_{0}}(1+\alpha \times 100)\]                    ... (ii) On dividing Eq. (i) by (ii) and solving it, we get                 \[\alpha =\frac{1}{200}\Omega /{{0}^{o}}C\] On putting in Eq. (i), we get                 \[5R={{R}_{0}}\left( 1+\frac{1}{4} \right)\] \[\Rightarrow \]               \[5R=\frac{5}{4}{{R}_{0}}\] \[\Rightarrow \]               \[{{R}_{0}}=4R\Omega \]


You need to login to perform this action.
You will be redirected in 3 sec spinner