MYP Physics · 16 · data analysis
Distance from stellar parallax
Space physics · Original GioPhysics question with a detailed, mark-by-mark answer guide.
- Demand
- routine
- Marks
- 6
- Topics
- 1
- Answer
- Complete
For nearby stars, distance in parsecs can be estimated using d = 1 ÷ p, where p is the parallax angle in arcseconds.
| Star | Parallax p / arcsec | Uncertainty / arcsec |
|---|---|---|
| K | 0.50 | ±0.01 |
| L | 0.20 | ±0.01 |
| M | 0.05 | ±0.01 |
- a
Calculate Calculate the distance to stars K and L.
2 marks - b
Analyse Identify which distance is least reliable and justify your choice from the table.
2 marks - c
Explain Explain why parallax becomes difficult to use for very distant stars.
2 marks
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a
Calculate Calculate the distance to stars K and L.
Read the data before explaining it. Quote the relevant values or trend, show the comparison or calculation, and then connect that numerical evidence to the physical conclusion—including uncertainty or anomalies when they matter.
- 1
Calculates dK = 1 ÷ 0.50 = 2.0 pc.
- 2
Calculates dL = 1 ÷ 0.20 = 5.0 pc.
b
Analyse Identify which distance is least reliable and justify your choice from the table.
Read the data before explaining it. Quote the relevant values or trend, show the comparison or calculation, and then connect that numerical evidence to the physical conclusion—including uncertainty or anomalies when they matter.
- 1
Identifies star M as having the least reliable calculated distance.
- 2
Explains that ±0.01 arcsec is the largest percentage uncertainty for M: 0.01 ÷ 0.05 = 20%.
c
Explain Explain why parallax becomes difficult to use for very distant stars.
Read the data before explaining it. Quote the relevant values or trend, show the comparison or calculation, and then connect that numerical evidence to the physical conclusion—including uncertainty or anomalies when they matter.
- 1
States that parallax angle becomes smaller as distance increases.
- 2
Explains that the angle approaches the instrument's resolution or becomes comparable with measurement uncertainty.
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