Uttarakhand PMT Uttarakhand PMT Solved Paper-2008

  • question_answer
    Two waves having intensities in the ratio of 9:1 produce interference. The ratio of maximum to minimum intensity is equal:

    A)  10 : 8          

    B)  9 : 1

    C)  4 :1           

    D)  2 : 1

    Correct Answer: C

    Solution :

     \[\frac{{{I}_{1}}}{{{I}_{2}}}=\frac{a_{1}^{2}}{a_{2}^{2}}=\frac{9}{1}\] \[\Rightarrow \] \[\frac{{{a}_{1}}}{{{a}_{2}}}=\sqrt{\frac{9}{1}}\] \[\Rightarrow \] \[\frac{{{a}_{1}}}{{{a}_{2}}}=\frac{3}{1}\] Then,      \[\frac{{{I}_{\max }}}{{{I}_{\min }}}=\frac{{{({{a}_{1}}+{{a}_{2}})}^{2}}}{{{({{a}_{1}}-{{a}_{2}})}^{2}}}\] \[=\frac{{{(3+1)}^{2}}}{{{(3-1)}^{2}}}\] \[=\frac{{{(4)}^{2}}}{{{(2)}^{2}}}=\frac{16}{4}\] \[=\frac{4}{1}\] Thus, \[{{I}_{\max }}:{{I}_{\min }}=4:1\]


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