This question is about analysing the electromagnetic radiation from the star Sigma Phoenicis.
The peak wavelength of electromagnetic radiation from Sigma Phoenicis is 330 nm330 \text{ nm}330 nm. The surface temperature of the Sun is 5800 K5800 \text{ K}5800 K and the wavelength at which its maximum intensity is emitted is 500 nm500 \text{ nm}500 nm.
The luminosity of Sigma Phoenicis is 5.2×1028 W5.2 \times 10^{28} \text{ W}5.2×1028 W.
Show that the surface temperature of Sigma Phoenicis is approximately 8800 K8800 \text{ K}8800 K.
Estimate the radius of Sigma Phoenicis.
Electromagnetic radiation is collected from Sigma Phoenicis by a sensor on Earth with an efficiency of 12%12\%12% and cross-sectional area 3.5×10−4 m23.5 \times 10^{-4} \text{ m}^23.5×10−4 m2. The radiant power detected by the sensor is 8.4×10−15 W8.4 \times 10^{-15} \text{ W}8.4×10−15 W.
Calculate the intensity (radiant power per unit area) of the radiation arriving at the sensor from Sigma Phoenicis.
Calculate the distance of Sigma Phoenicis from Earth in light years.
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.