2. Questions Bank
  3. 9th Class
  4. Science
  5. Gravitation and Floatation

9th Class Science Gravitation and Floatation Question Bank Gravitation IIT JEE Objective Problems

  • question_answer
    Taking that Earth revolves round the Sun in a circular orbit of radius\[1.5\times {{10}^{10}}m\]. with a time period of 1 year, the time taken by another planet, which is at a distance of \[\text{54}0\times \text{1}{{0}^{\text{1}0}}\text{ m}\], to revolve round the Sun in circular orbit once will be

    A)  216 yrs                

    B)  144 yrs

    C)  72 yrs                  

    D)  36 yrs

    Correct Answer: A

    Solution :

     
    Earth Planet
    \[{{R}_{1}}=1.5\times {{10}^{10}}m\] \[{{R}_{2}}=54\times {{10}^{10}}\text{ }m\]
    \[{{T}_{1}}=1\text{ }year\] \[{{T}_{2}}=?\]
    We know that, \[{{T}^{2}}\propto {{R}^{3}}\] \[\Rightarrow \] \[T\propto {{R}^{3/2}}\] \[\Rightarrow \]\[\frac{{{T}_{2}}}{{{T}_{1}}}{{\left( \frac{{{R}_{2}}}{{{R}_{1}}} \right)}^{3/2}}\]\[\Rightarrow \]\[{{\left( \frac{54\times {{10}^{10}}}{1.5\times {{10}^{10}}} \right)}^{3/2}}\] \[\Rightarrow \]\[{{T}_{2}}={{(36)}^{3/2}}=216\]              


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