2. Solved Papers
  3. JAMIA MILLIA ISLAMIA

JAMIA MILLIA ISLAMIA Jamia Millia Islamia Solved Paper-2009

  • question_answer
        An electron moving with velocity\[2\times {{10}^{7}}m{{s}^{-1}}\] describes a circle in a magnetic field of strength\[2\times {{10}^{-2}}T\].If\[\left( \frac{e}{m} \right)\]of electrons is\[1.76\times {{10}^{11}}K\,k{{g}^{-1}},\]then the diameter of the circle is nearly

    A)  1.1 cm                                 

    B)  1.1 mm

    C)  1.1 m                                   

    D)  11 cm

    Correct Answer: A

    Solution :

                    \[r=\frac{mv}{eB}\] \[=\frac{v}{\left( \frac{e}{m} \right)B}\] \[\therefore \]  \[r=\frac{2\times {{10}^{7}}}{1.76\times {{10}^{11}}\times 2\times {{10}^{-2}}}\] \[\Rightarrow \]               \[r=0.0056m\] \[\therefore \] \[D=2r\approx 0.011m\] \[D=1.1\,cm\]


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