DUMET Medical DUMET Medical Solved Paper-2005

  • question_answer
    The slit width, when a light of wavelength \[6500\overset{\text{o}}{\mathop{\text{A}}}\,\] is incident on a slit, if first minima for red light is at \[{{30}^{o}}\], is:

    A)  \[1\times {{10}^{-6}}\,m\]    

    B)  \[5.2\times {{10}^{-6}}\,m\]

    C)  \[1.3\times {{10}^{-6}}\,m\] 

    D)  \[2.6\times {{10}^{-6}}\,m\]

    Correct Answer: C

    Solution :

     When rays of monochromatic light of wavelength \[\lambda \] are incident on a diffraction grating in which slit separation is d, then for angle of diffraction 6, the following relation holds true. \[d\,\sin \theta =n\,\lambda \] where n is called the spectrum order. Given, \[n=1,\,\lambda =6500\,\overset{o}{\mathop{A}}\,=6500\times {{10}^{-10}}m\], \[\sin \,{{30}^{o}}=\frac{1}{2}\]. \[\Rightarrow \] \[d=\frac{n\,\lambda }{\sin \theta }\] \[\therefore \] \[d=\frac{6500\times {{10}^{-10}}}{(1/2)}\] \[d=1.3\times {{10}^{-6}}\,\,m\].  


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