M
Mike P
Guest
The Sun and all Main Sequence stars derive their luminosity by fusing hydrogen to helium; in particular
4 H → 1 He + Energy (photons)
The mass of a proton is 1.0078 AMU, while the mass of a helium nucleus is 4.0026 AMU.
a) How much mass is ``lost'' (in AMU and kg) in fusing four H atoms to one helium? This is called the mass defect.
b) Mass isn't really lost, of course. It is converted to energy via E=mc2. How much energy in joules
(J) is liberated in a single reaction?
c) How many reactions per second are required to account for the entire luminosity of the Sun?
d) How much mass (kg) does the Sun lose each second as a result?
e) What is the maximum lifetime of the Sun if it converts from the time of its birth to the time of its “death” 10% of its (present) mass into helium?
4 H → 1 He + Energy (photons)
The mass of a proton is 1.0078 AMU, while the mass of a helium nucleus is 4.0026 AMU.
a) How much mass is ``lost'' (in AMU and kg) in fusing four H atoms to one helium? This is called the mass defect.
b) Mass isn't really lost, of course. It is converted to energy via E=mc2. How much energy in joules
(J) is liberated in a single reaction?
c) How many reactions per second are required to account for the entire luminosity of the Sun?
d) How much mass (kg) does the Sun lose each second as a result?
e) What is the maximum lifetime of the Sun if it converts from the time of its birth to the time of its “death” 10% of its (present) mass into helium?