B2. A spherical star is detected by an astronaut in a spacecraft at a distance z of 1.5×10¹2 kilometers. The star can be regarded as a blackbody with a temperature of 11,300 K. The radius of the star is 3.5×106 kilometers. (a) Calculate the radiant exitance and the radiant intensity of the star. (b) Calculate the irradiance that can be detected by the astronaut. (c) The photodetector used by the astronaut in the spacecraft has a responsivity of 120 kV/W and an photosensitive area of 0.5 mm². Calculate the output voltage of the detector in the detection of the star.

B2. A spherical star is detected by an astronaut in a spacecraft at a distance z of 1.5×10¹2 kilometers. The star can be regarded as a blackbody with a temperature of 11,300 K. The radius of the star is 3.5×106 kilometers. (a) Calculate the radiant exitance and the radiant intensity of the star. (b) Calculate the irradiance that can be detected by the astronaut. (c) The photodetector used by the astronaut in the spacecraft has a responsivity of 120 kV/W and an photosensitive area of 0.5 mm². Calculate the output voltage of the detector in the detection of the star.