A 19th century lab technician is testing possible metals for bulb filaments. A tantalum filament with a surface area of 0.370 mm2 and an emissivity of 0.965 radiates 0.80 W of light. Determine the filament's temperature (in K). The melting point for tantalum is 3269 K.

Explanation:

The given data is as follows.

       A = 0.370 =

    emissivity () = 0.965,     E = 0.80 W

As we know that,

where,   s = Stefan-Boltzmann constant =

Now, putting the given values into the above formula as follows.

            2.162 =

          39516271.13 =

             T = 79.28 K

Thus, we can conclude that the filament's temperature is 79.28 K.

c. magnitude and direction