Question

A sphere, a cube and a thin circular plate have the same mass and are made of the same material. All of them are heated to the same temperature. The rate of cooling is:
A. Minimum for the plate
B. Minimum for the sphere
C. Maximum for the plate
D. Same for all the three

Answer 1

First we have to check the density, mass and volume for the sphere, cube and plate. And then compare with the surface area to get the answer.

Complete step by step answer:
Given,
The sphere, cube and plate are all made out of the same material. So, their density will also be the same.
Since mass is same and density is also same for all the materials their volume must also be equal.
If we compare the size occupied, the surface area of the plate is the highest followed by the cube and at last the sphere.
So, the sphere has the smallest surface area.
Also, we know that-
Each individual particle on an object’s surface is involved in the mechanism of heat conduction. There are more surface particles in an object with a larger region that function to conduct heat. As such, the heat transfer rate is directly proportional to the region of the surface from which the heat is carried out.
Hence, we can say that the rate of cooling is minimum for the sphere and maximum for the plate.

So, the correct answers are “Option B and C”.

Additional Information:
Additional Data (in points)

Note:
Here we have to see whether the objects are made of the same material or not. And even if they have the same material they have the same mass and volume or not. Only then the surface area will be the same.