There is a cylindrical shape sweet potato with an initial uniform temperature of 25°C and it has an average diameter of 70 mm and length of 150 mm. Thermal conductivity and diffusivity of the sweet potato are 0.62 W/m · °C and 0.2 x 10-6 m2/s, respectively. It is to be cooled by refrigerated air at 1.8°C. The average heat transfer coefficient between the potato and the air is 25 W/m2 · °C. Determine how long it will take for the center temperature of the potato to drop to 5.5°C.

Explanation:

The given data is as follows.

    ,    d = 70 mm =

    k = 0.62 ,    

    ,    v = 4 m/sec

       h = 25 ,  

First, we will calculate the value of as follows.

                    =

                    = 0.7056

Since, 0.7056 is greater than 0.1.

As,   = 0.159

                = 0.16

Also here,

              = 1.9

            = 1.9

                 T = 46.18 hrs

Thus, we can conclude that it will take 46.18 hrs for the center temperature of the potato to drop to .

c.is a substance that requires a small amount of energy per gram to raise its temperature; has strong cohesive forces between molecules.

explanation:

a colorless, transparent, odorless liquid that forms the seas, lakes, rivers, and rain and is the basis of the fluids of living organisms.