2. Questions Bank
  3. JEE Main & Advanced
  4. Physics
  5. Photo Electric Effect, X- Rays & Matter Waves

JEE Main & Advanced Physics Photo Electric Effect, X- Rays & Matter Waves Question Bank Critical Thinking

  • question_answer
    The potential energy of a particle of mass m is given by \[U(x)=\left\{ \begin{align}   & {{E}_{0}};\ \ \ 0\le x\le 1 \\  & \,0\ ;\ \ \ \,\,\,\,x>1 \\ \end{align} \right.\]l1 and l2 are the de-Broglie wavelengths of the particle, when 0 £ x £ 1 and x > 1 respectively. If the total energy of particle is 2E0, the ratio \[\frac{{{\lambda }_{1}}}{{{\lambda }_{2}}}\] will be  [Based on IIT-JEE (Mains) 2005]

    A)            2    

    B)            1

    C)            \[\sqrt{2}\]

    D)            \[\frac{1}{\sqrt{2}}\]

    Correct Answer: C

    Solution :

                       K.E.= 2 E0? E0 = E0  (for 0 £ x £ 1)  Þ \[{{\lambda }_{1}}=\frac{h}{\sqrt{2m\,{{E}_{0}}}}\]                    K.E. = 2 E0 (for x > 1) Þ \[{{\lambda }_{2}}=\frac{h}{\sqrt{4m\,{{E}_{0}}}}\]\[\Rightarrow \frac{{{\lambda }_{1}}}{{{\lambda }_{2}}}=\sqrt{2}.\]


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