2. Questions Bank
  3. 12th Class
  4. Physics
  5. Magnetism

12th Class Physics Magnetism Question Bank Case Based (MCQs) - Moving Charges and Magnetism

  • question_answer
    A charged particle is projected in a magnetic field\[\overrightarrow{B}=(2\widehat{i}+4\widehat{j})\times {{10}^{2}}T\]. The acceleration of the particle is found to be \[\overrightarrow{a}=(x\widehat{i}+2\widehat{j})m{{s}^{-2}}\]. Find the value of x.

    A)     \[4\,m{{s}^{-2}}\]                   

    B) \[-4\,m{{s}^{-2}}\]

    C)             \[-2\,m{{s}^{-2}}\]      

    D)             \[2\,m{{s}^{-2}}\]

    Correct Answer: B

    Solution :

    (b) \[-4\,m{{s}^{-2}}\] As \[F\bot B\] Hence,  \[a\bot B\] \[\therefore \overrightarrow{a}\cdot \overrightarrow{B}=0\] \[\Rightarrow \,\,(x\,\widehat{i}\,+\,2\,\widehat{j})\cdot (2\,\widehat{i}\,+\,4\,\widehat{j})=0\] \[2x+8=0\Rightarrow x=-4\,m{{s}^{-2}}\]


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