JEE Main & Advanced Physics Photo Electric Effect, X- Rays & Matter Waves Question Bank Self Evaluation Test - Dual Nature of Radiation and Matter

  • question_answer
    Light of wavelength 180 nm ejects photoelectron from a plate of a metal whose work function is 2 eV. If a uniform magnetic field of \[5\times {{10}^{-5}}T\] is applied parallel to plate, what would be the radius of the path followed by electrons ejected normally from the plate with maximum energy?

    A) 1.239 m

    B) 0.149 m

    C) 3.182 m

    D) 2.33 m

    Correct Answer: B

    Solution :

    [b] If \[{{v}_{\max }}\] is the speed of the fastest electron emitted from the metal surface, then \[\frac{hc}{\lambda }={{W}_{0}}+\frac{1}{2}mv_{\max }^{2}\] \[\frac{\left( 6.63\times {{10}^{-34}} \right)\times \left( 3\times {{10}^{8}} \right)}{\left( 180\times {{10}^{-9}} \right)}\] The radius of the electron is given by \[r=\frac{mv}{qB}=\frac{\left( 9.1\times {{10}^{-31}} \right)\times \left( 1.31\times {{10}^{6}} \right)}{\left( 1.6\times {{10}^{-19}} \right)\times \left( 5\times {{10}^{-9}} \right)}=0.149m\]


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