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JEE Main 20249 AprilMorning Shift
Exam
JEE Main
Year
2024
Date
9 April
Shift
Morning Shift
Subject
Physics
Chapter
Nuclear Physics

JEE Main 2024 · 9 April · Morning Shift · Physics · Nuclear Physics

A star has 100 \% helium composition. It starts to convert three ^4...

A star has 100%100 \% helium composition. It starts to convert three 4He{ }^4 \mathrm{He} into one 12C{ }^{12} \mathrm{C} via triple alpha process as 4He+4He+4He→12C+Q{ }^4 \mathrm{He}+{ }^4 \mathrm{He}+{ }^4 \mathrm{He} \rightarrow{ }^{12} \mathrm{C}+\mathrm{Q}. The mass of the star is 2.0×1032 kg2.0 \times 10^{32} \mathrm{~kg} and it generates energy at the rate of 5.808×1030 W5.808 \times 10^{30} \mathrm{~W}. The rate of converting these 4He{ }^4 \mathrm{He} to 12C{ }^{12} \mathrm{C} is n×1042 s−1\mathrm{n} \times 10^{42} \mathrm{~s}^{-1}, where n\mathrm{n} is _________ [ Take, mass of 4He=4.0026u{ }^4 \mathrm{He}=4.0026 \mathrm{u}, mass of 12C=12u{ }^{12} \mathrm{C}=12 \mathrm{u} ]

Correct answer

0

Step-by-step solution

4He+4He+4He→12C+Q{ }^4 \mathrm{He}+{ }^4 \mathrm{He}+{ }^4 \mathrm{He} \rightarrow{ }^{12} \mathrm{C}+\mathrm{Q} power generated =NtQ=\frac{\mathrm{N}}{\mathrm{t}} \mathrm{Q} where, N→\mathrm{N} \rightarrow No. of reaction /sec/ \mathrm{sec}. Q=(3 mHe−mC)C2Q=(3×4.0026−12)(3×108)2Q=7.266MeV\begin{aligned} & \mathrm{Q}=\left(3 \mathrm{~m}_{\mathrm{He}}-\mathrm{m}_{\mathrm{C}}\right) \mathrm{C}^2 \\ & \mathrm{Q}=(3 \times 4.0026-12)\left(3 \times 10^8\right)^2 \\ & \mathrm{Q}=7.266 \mathrm{MeV}\end{aligned}Nt= power Q=5.808×10307.266×106×1.6×10−19Nt=5×1042\begin{aligned} & \frac{\mathrm{N}}{\mathrm{t}}=\frac{\text{ power }}{\mathrm{Q}}=\frac{5.808 \times 10^{30}}{7.266 \times 10^6 \times 1.6 \times 10^{-19}} \\ & \frac{\mathrm{N}}{\mathrm{t}}=5 \times 10^{42}\end{aligned}rateofconversionofrate of conversion of{ }^4 \mathrm{He}intointo{ }^{12} \mathrm{C}=15 \times 10^{42}Hence,Hence,\mathrm{n}=15$
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