An opaque spherical body of radius 1 km has a uniform photon intensity of 1 photon cm-2 s-1 hz-1 sterad-1 at frequencies between 1014 and 1015 hz. at all other frequencies it does not emit. what is its total luminosity in erg s-1?

What is a possible result of higher air temperature caused by global warming

The astronauts on the space shuttle flights experienced an acceleration of 29 m/s2 (about 3 "g's") during lift-off. what upward force must the astronaut's seat apply to the astronaut in order to cause this acceleration? assume the astronaut's mass is 70 kg, and compute this force when the acceleration is near the earth's surface so their weight equals latex: mg m g .

What is the efficiency of an engine that does 80 j of work and exhausts 320 j of heat while taking in 400 j of heat ? a. 10% b. 20% c. 80% d. 25%