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A star converts all its hydrogen to helium, achieving 100% helium composition. It then converts the helium to carbon via the reaction `._2He^4 + ._2He^4+ ._2He^4 to._6C^(12)+7.27MeV` The mass of the star is `5.0xx10^(32)kg` and it generates energy at the rate of `5xx10^(30)` watt. How long will it take to convert all the helium to carbon at this rate?

Answer» Correct Answer - `1.85xx10^8` year
Total number of helium atoms =`(6.023xx10^23)/(4xx10^(-3))xx5.0xx10^32` atoms
=`7.52875 xx10^58` atoms
3 helium atoms produce 7.27 MeV of energy =`7.27xx1.6xx10^(-13)`J
`"Total energy produced by all the atoms"/"Power"`=Time taken


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