2. Solved Papers
  3. JAMIA MILLIA ISLAMIA

JAMIA MILLIA ISLAMIA Jamia Millia Islamia Solved Paper-2010

  • question_answer
        Steady rain giving 5 mm an hour, turns suddenly into a downpour 20 mm an hour and the speed of rain drops falling vertically on to a flat roof simultaneously doubles. The pressure exerted by the falling rain on the roof rises by a factor of

    A)  2                                            

    B) \[2\sqrt{2}\]

    C)  \[4\sqrt{2}\]                                     

    D)  8

    Correct Answer: D

    Solution :

                    Force exerted by the falling rain drop on the roof\[=adpv\]where, \[a=\]area of the roof\[d=\]thickness of water layer formed due to rain\[\rho =\]density of water and  \[v=\]velocity of rain drops Since, rain falling suddenly increases from 5 mm/h to 20 mm/h, hence d increases to 4 times velocity is also doubled. Hence, becomes\[2v\]. Thus, the pressure\[\left( =\frac{F}{a} \right)\]exerted will become\[4\times 2=8\]times.       


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