Question

Question 16 (1 point) Visible light has wavelengths ranging between approximately 4000 and 7000 Angstroms (400 to 700 nanometres). Which of the following statements is true regarding the surface temperature of a star for which the wavelength of maximum intensity falls in the visible range t could never be cooler than 8000 K It must always be cooler than 5500 K t must lie between 8000 K and 5500 K It must always be hotter than 3500 K Question 17 (1 point) Saved Star A has a smaller radius and a higher surface temperature than star B.how do the luminosties of the two stars compare? Star A is more luminous than star B Star A is less luminous than Star B The luminosities of the two stars will be equal Not enough information is given to determine which of the above answers is correct

Answer 1

Lambda_m T = constant lambda_m T = 2.89777 times 10^-3 mk (4000 to 7000 A degrees) 4000 A degrees T_max T_max = (2.89777 times 10^-3/4000 times 10^-10) T_max = 7244.425 k 7000 A degrees T_min = 2.89777 times 10^-3/7000 times 10^-10 T_min = 4139.6714 k As we see 3rd option is correct one 8000 k to 5000 k