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QJEEM16Ph7982: JEE Main 2016 Physics - Class 12 JEEM16Ph7982 Solution: Two stars are 10 light years away from the earth. They are seen …

Two stars are 10 light years away from the earth. They are seen through a telescope of objective diameter 30 cm. The wavelength of light is 600 nm. To see the stars just resolved by the telescope, the minimum distance between them should be (1 light year = 9.46 ×\times 1015 m) of the order of :

Multiple Choice Options

  • A 106 km
  • B 108 km
  • C 1011 km
  • D 1010 km

Step-by-Step Verified Solution

The limit of resolution of a telescope,

Δ\Delta θ\theta   =   1.22  λD{{1.22\,\,\lambda } \over D} = lR{l \over R}

∴\therefore     ll = 1.22  λRD{{1.22\,\,\lambda R} \over D}

=    1.22×6×10−7×10×9.46×101530×10−2{{1.22 \times 6 \times {{10}^{ - 7}} \times 10 \times 9.46 \times 10{}^{15}} \over {30 \times {{10}^{ - 2}}}}

=   2.31 ×\times 108 km

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