Author Question: A giant star radiates energy at the rate of 3.0 1030 W, and its surface temperature has been ... (Read 92 times)

nummyann · **on:** Jul 29, 2018

A giant star radiates energy at the rate of 3.0 1030 W, and its surface temperature has been measured to be 3000 K. Assuming that it is a perfect emitter, what is the radius of this star? ( = 5.67 10-8 W/m2 K4)

A) 7.8 1010 m
B) 8.7 1010 m
C) 1.4 1010 m
D) 1.9 1011 m
E) 2.3 1011 m

Question 2

The radius of a star is 6.95 108 m, and its rate of radiation has been measured to be 5.32 1026 W. Assuming that it is a perfect emitter, what is the temperature of the surface of this star? ( = 5.67 10-8 W/m2 K4)

A) 6.27 103 K
B) 8.25 103 K
C) 8.87 103 K
D) 3.93 107 K
E) 5.78 107 K