Heat TransferEasy
Question
Two metallic spheres S1 and S2 are made of the same material and have got identical surface finish. The mass of S1 is thrice of S2. Both the spheres are heated to the same high temperature and placed in the same room having lower temperature but are thermally insulated from each other. The ratio of the initial rate of cooling of S1 to that of S2 is
Options
A.
B.
C.
D.
Solution
The rate at which energy radiates from the object is
= eσAT4
Since, ᐃQ = mc ᐃT , we get
Also, since m =
for a sphere, we get
A = 4π2r = 4π
Hence,
For the given two bodies
= eσAT4 Since, ᐃQ = mc ᐃT , we get
Also, since m =
for a sphere, we get A = 4π2r = 4π
Hence,
For the given two bodies
Create a free account to view solution
View Solution FreeMore Heat Transfer Questions
A black body is at temperature of 500 K, it emits energy at a rate which is proportional to :...If a piece of metal is heated to temperature θ and then allowed to cool in a room which is at temperature θ0 t...A wall is made up of two layers A and B. The thickness of the two layers is the same, but materials are different. The t...A piece of steel is heated upto 100oC and is allowed to cool in a room then which graph is correct ?...A sphere a cube and a thin circular plate all made of same substance and all have same mass. These are heated to 200oC a...