Physics
A circular plate, a cube and a sphere, all made up of same material and having the samemass, are heated to 300°C and left in a room. Which of them will have the slowest rate of cooling?
Circular plate
Cube
Sphere
All will cool at the same rate
Sphere
In the late of 17th century British scientist Isaac Newton studied cooling of bodies. Experiments showed that the cooling rate is approximately proportional to the difference of temperatures between the heated body and the environment. This fact can be written as the differential relation : dQ dt A T T S= abg, where A is the surface area of the body through which the heat is transferred, T is the temperature of the body, TS is the temperature of the surrounding environment, á is the heat transfer coefficient depending on the geometry of the body, state of the surface, heat transfer mode, and other factors. Surface area or volume ratio is an important influence on temperature control. For same volume sphere has minimum surface area, while circular plate has maximum surface area. So sphere cools slowest and plate cools fastest.
Sphere In the late of 17th century British scientist Isaac Newton studied cooling of bodies. Experiments showed that the cooling rate is approximately proportional to the difference of temperatures between the heated body and the environment. This fact can be written as the differential relation : dQ dt A T T S= abg, where A is the surface area of the body through which the heat is transferred, T is the temperature of the body, TS is the temperature of the surrounding environment, á is the heat transfer coefficient depending on the geometry of the body, state of the surface, heat transfer mode, and other factors. Surface area or volume ratio is an important influence on temperature control. For same volume sphere has minimum surface area, while circular plate has maximum surface area. So sphere cools slowest and plate cools fastest.
Related posts
Radian is used to measureA. Temperature
B. Intensity of Flame
C. Angle
D. Solid Angle
Flemings ”Left hand Rule” is associated with the effect of
A. Electric field on current
B. Magnetic field on magnet
C. Electric field on magnet
D. Magnetic Field on current
The sky appears blue due to
A. Rayleigh scattering
B. Mie scattering
C. Back scattering
D. None of the above
Vehicles use ________ to see the objects coming from behind.
A. Concave lens
B. Convex lens
C. Convex mirror
D. Concave mirror
Which elements are malleable and good conductors of electricity?
A. Tin and silver
B. Iodine and silver
C. Tin and xenon
D. Iodine and xenon
The colour of the ocean appears to be blue because the sunlight falling on it is
A. Reflected
B. Refracted
C. Diffracted
D. Scattered
Mach number is used in connection with the speed of
A. sound
B. aircraft
C. spacecraft
D. ships
Leave a Reply