The Gaia space observatory measures the trigonometric parallax of a distant Cepheid variable star to be 2.5×10−4 arcseconds2.5 \times 10^{-4}\text{ arcseconds}2.5×10−4 arcseconds.
What is the distance to this star in light-years (ly\text{ly}ly)?
(Use the following values: 1 pc=3.08×1016 m1\text{ pc} = 3.08 \times 10^{16}\text{ m}1 pc=3.08×1016 m, 1 ly=9.46×1015 m1\text{ ly} = 9.46 \times 10^{15}\text{ m}1 ly=9.46×1015 m)
4.0×103 ly4.0 \times 10^3\text{ ly}4.0×103 ly
1.2×103 ly1.2 \times 10^3\text{ ly}1.2×103 ly
1.3×104 ly1.3 \times 10^4\text{ ly}1.3×104 ly
8.2×10−4 ly8.2 \times 10^{-4}\text{ ly}8.2×10−4 ly
66 exam-style questions on OCR A A Level Physics Astrophysics and cosmology, covering Stars, Electromagnetic radiation from stars, and Cosmology. Each one has a worked solution and a mark scheme showing where the marks go.