Heat Transter Three Modes: ConducHon: Hhen kere is a medium carryng heat and that medium is hastionary T, Convection When medium camging heat 4 in motion Hot Plate "> Radiation: when there ,w noinvolvement medium and heat is carrie^ by photon e g Radation of Sun reaching to easth
Conducon 8. 2 2 Assumptions:- Heat leaving body at T = Heat reaching body at Ta "t There is no heat e behueen mediurm and Surssoundim "> The medium ; at teady state. This means heat is not being used to chmge temp of lhe medium
emperature radient Let, lemp- Variation acron dx = dT 2 dx Temp grad- dT = Rate of change cf temp. with ength of medium If grad, is uniform.
Rate of Heat Flo in Conducton 8 2 = Rate of heat Kaw = Heat 6Lowr p en unit time We may observe (A area of cro-secon) 2 conduckvity of matena Final equation Js in direchon decreatirg lemp)
Example+ A rod of lengh m andro-sectional area 2 cm2 placed between a Annce &f constant "P 5d'c ond om ice box Containin ha of ice at 'c it taxes 5 mito melt alu th ice Hhen bind
Solution ice 50 (Cons tomt 0 Magnitude of = provided to ce in o0 Heat 5 min = mx300 = 3K By Energy conservahor, = mLf 3K= 5003 80x4.2J
Example Two voda of equal length. have rada us R 2R and Conduchwies 2K and K res pecti amanfed as hern in above tguretemp vely Ty ne
Solution (g lo C Asuming no heat losses, nol C2nd yod) St -) 2 (60-T)= 41T-lo) 80 C 3 26.6 C
I have done B.Tech, IIT Delhi (in Mechanical engineering). I have been teaching physics to JEE and NEET aspirants for three years.