CET Karnataka Engineering CET - Karnataka Engineering Solved Paper-2004

  • question_answer
    A wire has a resistance of \[6\,\Omega \]. It is cut into two parts and both half values are connected in parallel. The new resistance is:

    A)  \[3\,\Omega \]                               

    B)  \[6\,\Omega \]

    C)  \[12\,\,\Omega \]                          

    D)  \[1.5\,\,\Omega \]

    Correct Answer: D

    Solution :

    Resistance of original wire is                 \[R=\rho \frac{l}{A}\] \[\rho \], being the specific resistance of wire. When the wire is cut in two equal halves then resistance becomes                 \[R=\frac{\rho \,I/2}{A}=\frac{R}{2}\] Thus, the net resistance of parallel combination of two halves is given by \[{{R}_{net}}=\frac{R\times R}{R+R}=\frac{R}{2}=\frac{R}{2\times 2}=\frac{6}{4}=1.5\,\,\Omega \]


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