A researcher estimates the total main sequence lifetime of a massive star in a distant galaxy.
The researcher uses this model:
time on main sequence=mass of usable hydrogen÷rate at which hydrogen is used\text{time on main sequence} = \text{mass of usable hydrogen} \div \text{rate at which hydrogen is used}time on main sequence=mass of usable hydrogen÷rate at which hydrogen is used
| Quantity | Value |
|---|---|
| mass of usable hydrogen in the core | 6.0 × 1030 kg |
| rate at which hydrogen is used | 4.0×1023 kg per year4.0 \times 10^{23}\ \text{kg per year}4.0×1023 kg per year |
Calculate the mass of hydrogen used by the star in one million years.
Calculate the total main sequence lifetime of the star.
State what has happened to the hydrogen in the core when the star reaches the end of its main sequence stage.
75 exam-style questions on Edexcel GCSE Physics 7.3 Stars, covering 7.3.1 Evolution of stars similar to the Sun, 7.3.2 Evolution of massive stars, and 7.3.3 Observing the Universe. Each one has a worked solution and a mark scheme showing where the marks go.