NEET Sample Paper NEET Sample Test Paper-75

  • question_answer
    At what height from above the surface of earth, then value of acceleration due to gravity reduces to half of its present value (radius of earth =6400 km)

    A)  2660.0 km                   

    B)  2689.0 km

    C)  2559.6 km                   

    D)  2649.6 km

    Correct Answer: D

    Solution :

    Let g be acceleration due to gravity on earth and g? be acceleration due to gravity at height h Then, \[\frac{g'}{g}={{\left( \frac{R}{R+H} \right)}^{2}}\] Given,   \[\frac{g'}{g}=\frac{1}{2}\] \[\frac{1}{2}={{\left( \frac{R}{R+H} \right)}^{2}}\] \[\frac{R}{R+H}=\frac{1}{\sqrt{2}}\,\,\,\Rightarrow \,\,\frac{h}{R}\,=\sqrt{2}-1=0.414\] So,        \[h\,\,=\, 0.414 \times \,\,R\] \[=\,\,\,0.414\,\,\times \,\,6400 km\] \[\operatorname{V}\,\,=\, 2649.6 km\]


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