Q. Consider the following statements :
Statement-I : Giant stars live much longer than dwarf stars.
Statement-II : Compared to dwarf stars, giant stars have a greater rate of nuclear reactions.
Which one of the following is correct in respect of the above statements?
- Both Statement-I and Statement-II are correct and Statement-II explains Statement-I
- Both Statement-I and Statement-II are correct, but Statement-II does not explain Statement-I
- Statement-I is correct, but Statement-II is incorrect
- Statement-I is incorrect, but Statement II is correct
Answer: (d) Statement-I is incorrect, but Statement II is correct
Notes:
- Giant stars do not live much longer than dwarf stars. In fact, giant stars have shorter lifespans than dwarf stars. Giant stars, due to their larger mass and higher core temperatures, burn through their nuclear fuel much more rapidly, leading to shorter lifespans.
- Dwarf stars, especially red dwarfs, can have lifespans of tens to hundreds of billions of years, while giant stars typically live for millions to a few billion years.
- Giant stars have a much higher rate of nuclear reactions compared to dwarf stars. This is because they have larger masses and hotter, denser cores, which accelerate the fusion processes.
| Feature | Giant Stars | Dwarf Stars |
|---|---|---|
| Mass | 8-100 times the mass of the Sun | Less than 5 times the mass of the Sun |
| Size | Much larger than the Sun (up to 1,000 times wider) | Smaller than the Sun |
| Lifespan | Shorter, millions to a few billion years | Longer, tens to hundreds of billions of years |
| Luminosity | Much brighter than the Sun | Dimmer than the Sun |
| Core Temperature | Higher than dwarf stars | Lower than giant stars |
| Nuclear Reactions | Higher rate of nuclear reactions | Lower rate of nuclear reactions |
| Evolutionary Path | Can become red giants or supergiants before ending as neutron stars or black holes | Typically become white dwarfs or red dwarfs after the main sequence |
