Since stars emit light in almost exactly the same fashion as blackbodies. we can
ID: 1414338 • Letter: S
Question
Since stars emit light in almost exactly the same fashion as blackbodies. we can use the Stefan-Boltzmann law to relate a star's luminosity (L), surface temperature (T), and radius (R). The relevant equation is L = 4 pi R^2 standard deviation T^4 In many calculations it is more convenient to relate everything to the Sun, which is a typical star. Specifically for the Sun we have L_circled dot operator = 4 pi R^2_circled dot operator standard deviation^4_circled dot operator where L_circled dot operator is the Sun's luminosity. R_circled dot operator and T_circled dot operator are the Sun's radius and temperature. Dividing the general equation for L by the specific equation for the Sun. we can find the radius of the star respect to the radius of the Sun. The bright reddish star Betelgeuse in the constellation Orion is 60000 times more luminous than the Sun and has a surface temperature of 3500K. What is its radius?Explanation / Answer
deviding the eqaution (1) by equation (2)
L/Lo =[ ( R / Ro )^2 ] * [ (T / To)^4 ]
60000 = [ (R / Ro)^2 ] * [ (3500)^4 ]
( R / Ro )^2 = 3.99833403 * 10^(-10)
radius respect to sun R / Ro = 0.0000199958 meter ......................Ans..