Liquid helium is stored at its boiling-point temperature of4.2
k in a spherical container (r = 0.589 m). thecontainer is
a perfect blackbody radiator. the container issurrounded by a
spherical shield whose temperature is 58.4 k. avacuum exists in the
space between the container and shield. thelatent heat of
vaporization for helium is 2.1 x 104j/kg. what mass of
liquid helium boils away through the ventingvalve in 6.76
hours?

Explanation:

Given data:

Radius of contaner = 0.589 m

emissivity is  = 1

surface area =

Net Radiation between heilum and shell is given as

for 6.76 hr = 70,087.68 J/hr

rate of energy removed can be calculated by using the following relation

solving for \dot m we get

as we know our atmosphere or air have different levels. every level has other gasses, and every gas has another permeability. when the light comes from lower permeability to higher permeability, it changes its direction. so that means that when the light comes from the moon to the earth, it changes it's direction many more times. it basically means that the shape of the light part of the moon is changed on the earth.

hope this ! this is not copied! search it up, it's free of plagiarism!