Uttarakhand PMT Uttarakhand PMT Solved Paper-2008

  • question_answer
    How many seconds are there in a light fermi?

    A)  \[{{10}^{-15}}s\]        

    B)  \[3.0\times {{10}^{8}}s\]

    C)  \[3.33\times {{10}^{-24}}s\]   

    D)  \[3.3\times {{10}^{-7}}s\]

    Correct Answer: C

    Solution :

     One light fermi is time taken by light to travel a distance of 1 fermi ie,\[{{10}^{-15}}m\]. As         \[t=\frac{l}{v}\] \[\therefore \]1 light fermi \[=\frac{{{10}^{-15}}}{3\times {{10}^{8}}}\] \[=\frac{1\times {{10}^{-23}}}{3}\] \[=0.333\times {{10}^{-23}}\] \[=3.33\times {{10}^{-24}}s\]


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