CEE Kerala Engineering CEE Kerala Engineering Solved Paper-2007

  • question_answer
    A potentiometer wire, 10 m long, has a resistance of\[40\,\Omega \]. It is connected in series with a resistance box and a 2 V storage cell. If the potential gradient along the wire is (0.1 mV/cm), the resistance unplugged in the box is

    A)  \[260\,\Omega \]                           

    B)  \[760\,\Omega \]           

    C)         \[960\,\Omega \]           

    D)         \[1060\,\Omega \]

    E)  \[1160\,\Omega \]

    Correct Answer: B

    Solution :

    Potential gradient along wire \[=\frac{potential\text{ }difference\text{ }along\text{ }wire}{length\text{ }of\text{ }wire}\] \[\therefore \]  \[0.1\times {{10}^{-3}}=\frac{I\times 40}{1000}V/cm\] Current in wire,                 \[I=\frac{1}{400}A\] Or           \[I=\frac{E}{R+R}\] \[\therefore \]  \[\frac{2}{40+R}=\frac{1}{400}\] Or           \[R=800-40=760\,\Omega \]


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