The total mass of the Sun is about 2×1030 kg, of which about 74 % was hydrogen w
ID: 283009 • Letter: T
Question
The total mass of the Sun is about 2×1030 kg, of which about 74 % was hydrogen when the Sun formed. However, only about 14 % of this hydrogen ever becomes available for fusion in the core. The rest remains in layers of the Sun where the temperature is too low for fusion.
1. Use the given data to calculate the total mass of hydrogen available for fusion over the lifetime of the Sun.
m = ? kg (In two significant figure)
2. The Sun fuses about 600 billion kilograms of hydrogen each second. Based on your result from part A, calculate how long the Sun’s initial supply of hydrogen can last. Give your answer in both seconds and years.
t = ? s (In two significant figure)
3. t = ? years (In two significant figure)
4. Given that our solar system is now about 4.6 billion years old, when will we need to worry about the Sun running out of hydrogen for fusion?
t = ? Billion years (In two significant figure)
Explanation / Answer
mass of the Sun = 2 * 1030 kg
Hydrogen = 74% of MSun and available hydrogen is 14% of this
Hydrogen = 74/100 * 2 * 1030 = 1.48 * 1030 kg
Available hydrogen for fusion = (14/100) * 1.48 * 1030
= 2.07 * 1029 kg
------------------------------------------------------
Total lifetime of sun = 2.07 * 1029 kg / 600 * 109
= 3.45 * 1017 s
Total lifetime of sun in years = 3.45 * 1017 / (365 * 24 * 60 * 60)
= 10.95 * 109 years
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.