A galaxy at a distance of 2.5 × 1021 km is moving away from Earth with a speed of 6000 km/s. What is the Hubble constant H0 H_0\,H0 calculated using this data, and what is the speed of a galaxy at a distance of 7.5 × 1021 km from Earth?
H0=2.4×10−18 s−1H_0 = 2.4 \times 10^{-18}\text{ s}^{-1}H0=2.4×10−18 s−1, speed = 2000 km/s2000\text{ km/s}2000 km/s
H0=2.4×10−18 s−1H_0 = 2.4 \times 10^{-18}\text{ s}^{-1}H0=2.4×10−18 s−1, speed = 18000 km/s18000\text{ km/s}18000 km/s
H0=4.2×1017 s−1H_0 = 4.2 \times 10^{17}\text{ s}^{-1}H0=4.2×1017 s−1, speed = 2000 km/s2000\text{ km/s}2000 km/s
H0=4.2×1017 s−1H_0 = 4.2 \times 10^{17}\text{ s}^{-1}H0=4.2×1017 s−1, speed = 18000 km/s18000\text{ km/s}18000 km/s
59 exam-style questions on CIE IGCSE Physics 6.2.3a Galaxies and the scale of the Universe. Each one has a worked solution and a mark scheme showing where the marks go.