CET Karnataka Medical CET - Karnataka Medical Solved Paper-2000

  • question_answer
    The resistance of a conductor is 5 ohm at \[50{}^\circ C\] and 6 ohm at \[100{}^\circ C\]. Its resistance at \[0{}^\circ C\] is:

    A)  1 ohm

    B)  2 ohm

    C)   3 ohm

    D)  4 ohm

    Correct Answer: D

    Solution :

     From the formula \[R={{R}_{0}}(1+\alpha t)\] \[\text{Ist}\] case at \[50{}^\circ C\], we have \[5={{R}_{0}}(1+50\alpha )\] ...(1) \[\text{IInd}\] case at \[100{}^\circ C\], we have \[6={{R}_{0}}(1+100\alpha )\] ...(2) Now dividing equation (2) by equation (1), we get \[\frac{6}{5}=\frac{1+100\alpha }{1+50\alpha }\] \[6+300\alpha =5+500\alpha \] so \[\alpha =\frac{1}{200}\] Again after putting the value of \[\alpha \] in equation (1), we get \[5={{R}_{0}}\left( 1+50\times \frac{1}{200} \right)\] \[{{R}_{0}}=\frac{20}{5}=4ohm\]


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