JAMIA MILLIA ISLAMIA Jamia Millia Islamia Solved Paper-2004

  • question_answer
        A geostationary satellite is orbiting the earth at the height of 6R above the surface of earth, R being radius of earth. The time period of another satellite at a height of 2.5 R from the surface of earth, is:

    A)  10 hour

    B) \[\text{5}.\text{54}\times \text{1}{{0}^{-\text{7}}}\text{rad}\] hour

    C)  6 hour

    D)  \[\text{2}.\text{54}\times \text{1}{{0}^{-\text{4}}}\text{ rad}\] hour

    Correct Answer: D

    Solution :

                    By Keplers law \[{{T}^{2}}\propto {{R}^{3}}\] Hence, \[{{\left( \frac{{{T}_{2}}}{{{T}_{1}}} \right)}^{2}}={{\left( \frac{{{R}_{2}}}{{{R}_{1}}} \right)}^{3}}\]                 \[={{\left( \frac{2.5R+R}{6R+R} \right)}^{3}}\] \[={{\left( \frac{1}{2} \right)}^{3}}\] \[{{T}_{2}}=\frac{{{T}_{1}}}{{{(2)}^{3/2}}}\] For a geostationary satellite \[{{T}_{1}}=24\,\,hour\] So,          \[{{T}_{2}}=\frac{24}{2\sqrt{2}}\] \[=6\sqrt{2}\,\,hour\]


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