Asubstance can absorb or release heat energy by the process of

A substance can absorb or release heat energy by the process of radiation, convection, or conduction. Radiation refers to the transfer of energy through emission of electromagnetic waves or the movement of particles. An example of radiation is the Sun’s rays. This type of heat transfer does not require direct contact between objects. Convection, on the other hand, involves the hotter fluid rising while the colder fluid sinks. Convection occurs when you boil water in a pan. Lastly, conduction is a heat transfer that occurs as a result of temperature difference between two objects in contact. Heat is transferred from the hotter region to the colder region. Conduction occurs when ice melts in your hands. 

2b2t

explanation:

2b2t

answer: semi-infinite solid initially at a uniform temperature of 400 ◦c is cooled at its surface by convection. the cooling fluid at a constant temperature of 200 ◦c has a convective coefficient (ha) of 250 w/m2.k. the physical properties of the solid: k = 20 w/m.k and α = 4 * 10-5  m2/s. using δx = 0.04 m and δt = 10 s. write the finite difference equations describing the transient heat transfer of the first five δx and the temperature profile after 30 s.