Consider a sealed 20 cm high electronic box whose base dimensions are 40cm x 40cm placed in a vacuum chamber. The emissivity of the outer surface of the box is 0.95. If the electronic components in the box dissipate a total of 100 W of power and the outer surface temperature of the box is not to exceed 55 C, determine the temperature at which the surrounding surfaces must be kept if this box is to be cooled by radiation alone. Assume the heat transfer from the bottom of the box to the stand to be negligible.

In Celsius:

Explanation:

The formula we are going to use is:

Where:

ε is the emissivity

σ is the Stefan constant

is the final temperature of surrounding surfaces

is the required temperature

is the are of surrounding surface

Calculating The area:

σ=

ε =0.95

=55+273

=328 K

=100 W

In Celsius:

they are non-matter

explanation:

they are non-matter. basically, any type of energy or any abstract concept is an example of something that does not matter. other examples include dreams, magnetism, radio, and hate

temp rises, and expansion