Astrophysicists analyzing the habitable zone of a newly catalogued star system, Gliese-X, measure the host star's radiant power output to be 6.4 × 1026 W. An Earth-like exoplanet orbits this star at an average distance of 3.1 × 1011 m.
The intensity of electromagnetic radiation, III, received at a distance d d\,d from a star of power output P P\,P is given by the formula:
I=P4πd2 I = \frac{P}{4 \pi d^2} I=4πd2PCalculate the intensity of the radiation incident on the exoplanet's atmosphere.
Give your answer to 2 significant figures and state the appropriate unit.
28 exam-style questions on Edexcel GCSE Physics 7.1 The Solar System and gravity, covering 7.1.1 Weight and g on different bodies in space, 7.1.2 The Solar System, 7.1.3 Changing ideas about the Solar System, 7.1.4 Orbits of moons, planets, comets and satellites, and 7.1.5 Gravity and orbital motion. Each one has a worked solution and a mark scheme showing where the marks go.