JEE Main & Advanced JEE Main Paper (Held On 19 April 2014)

  • question_answer
    The electric field in a region of space is given by, \[\vec{E}={{E}_{o}}\hat{i}+2{{E}_{o}}\hat{j}\]where \[{{E}_{o}}=100N/C.\]The flux of the field through a circular surface of radius 0.02 m parallel to the YZ plane is nearly:     JEE Main Online Paper (Held On 19 April 2016)

    A) 0.125 Nm2/C     

    B) 0.02 Nm2/C

    C) 0.005 Nm2/C     

    D) 3.14 Nm2/C

    Correct Answer: A

    Solution :

    \[\overset{\to }{\mathop{E}}\,={{E}_{0}}\hat{i}+2{{E}_{0}}\hat{j}\] Given, \[{{E}_{0}}=100N/c\] So, \[\overset{\to }{\mathop{E}}\,=100\hat{i}+200\hat{j}\] Radius of circular surface = 0.02 m Area \[=\pi {{r}^{2}}=\frac{22}{7}\times 0.02\times 0.02\] \[=1.25\times {{10}^{-3}}\hat{i}\,{{m}^{2}}\][Loop is parallel to Y-Z plane] Now, flux \[(\phi )=EA\cos \theta \] \[=\left( 100\hat{i}+200\hat{j} \right).1.25\times {{10}^{-3}}\hat{i}\cos {{\theta }^{o}}[\theta ={{0}^{o}}]\] \[=1.25\times {{10}^{-3}}N\,{{m}^{2}}/c\] \[=0.125N\,{{m}^{2}}/c\]


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