JEE Main & Advanced Sample Paper JEE Main Sample Paper-45

  • question_answer
    A telescope has an objective lens of 10 diameter and is situated at a distance of 1 km from two objects. The minimum distance between these two objects, which can be resolved by the telescope, when the mean wavelength of light is \[5000\,\overset{o}{\mathop{\text{A}}}\,\], is of the order of

    A)  0.5m                          

    B)  5m            

    C)  6mm                          

    D)  7cm

    Correct Answer: C

    Solution :

     If \[x\] is the distance between two objects and d is the distance between the telescope and the two objects, then\[d\theta =\frac{x}{d}=\frac{1.22\lambda }{D}\] or \[x=\frac{1.22\lambda d}{D}=\frac{1.22\times 5000\times {{10}^{-10}}\times 1000}{0.10}m\] \[=6.0\times {{10}^{-3}}\,\approx \,\,\text{6}\,\,\text{mm}\]

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