Answer:
A. 1.8 ×
Kg
B i. 3.0 ×
seconds
ii. 9.6 ×
years
C. After 9.2 ×
(9.2 billion) years
Step-by-step explanation:
Given that the mass of the Sun = 2×
Kg.
Mass of hydrogen when Sun was formed = 76% of 2×
Kg
=
×2×
Kg
= 1.52 ×
Kg
Mass of hydrogen available for fusion = 12% of 1.52 ×
Kg
=
× 1.52 ×
Kg
= 1.824 ×
Kg
A. Total mass of hydrogen available for fusion over the lifetime of the sun is 1.8 ×
Kg.
B. Given that the Sun fuses 6 ×
Kg of hydrogen each second.
i. The Sun's initial hydrogen would last;

= 3.04 ×
seconds
The Sun's hydrogen would last 3.0 ×
seconds
ii. Since there are 31536000 seconds in a year, then;
The Sun's initial hydrogen would last;

= 9.640 ×
years
The Sun's hydrogen would last 9.6 ×
years.
C. Given that our solar system is now about 4.6 ×
years, then;

= 2.09
So that; 2 × 4.6 ×
= 9.2 ×
years
Therefore, we need to worry about the Sun running out of hydrogen for fusion after 9.2 ×
years.