The suns energy - question

Im totally stuck on this question:

The sun's energy is produced when hydrogen burns to form helium. 4 protons are required to make each helium nucleus. Use the data below to show that the number of helium nuclei created per second in the sun is approx 1 x 10^38

Data: mass of proton = 1.67 x 10^-27 kg
mass of helium nucleus = 6.64 x 10^-27 kg

Any help will be much appreciated.

Reply 1

F1 fanatic

calculate the mass difference between a 4 hydrogen atoms and 1 helium. This is the energy released in fusion in the form of mass energy.. ie you then use the famous formula E=mc^2 to convert mass to energy.

That gives the energy released in 1 fusion reaction, then you can use the data for the suns luminosity (hopefully on the data sheet) which is the total energy per second from all the reactions to calculate the number of reactions per second.