JEE Main & Advanced JEE Main Paper (Held On 11 April 2014)

  • question_answer
    Two monochromatic light beams of intensity 16 and 9 units are interfering. The ratio of intensities of bright and dark parts of the resultant pattern is:   [JEE Main Online Paper ( Held On 11 Apirl  2014 )

    A) \[\frac{16}{9}\]                                

    B) \[\frac{4}{3}\]

    C) \[\frac{7}{1}\]                                   

    D) \[\frac{49}{1}\]

    Correct Answer: D

    Solution :

                    Intensity \[\propto \](amplitude)2\[\frac{{{I}_{1}}}{{{I}_{2}}}=\frac{16}{9}=\frac{a_{1}^{2}}{a_{2}^{2}}\] \[\Rightarrow \]\[{{a}_{1}}=4;{{a}_{2}}=3\] Therefore the ratio of intensities of bright and dark parts\[\frac{{{I}_{Bright}}}{{{I}_{Dark}}}=\frac{{{({{a}_{1}}+{{a}_{2}})}^{2}}}{{{({{a}_{1}}-{{a}_{2}})}^{2}}}=\frac{{{(4+3)}^{2}}}{{{(4-3)}^{2}}}=\frac{49}{1}\]


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