A long iron rod initially at a temperature of 20°C has one end dipped in boiling water (100°C) at time, t = 0. The curved surface of the rod is insulated so that heat conduction is one dimensional in the axial direction. The temperature at a distance 100 mm from the dipped end becomes 40°C at time, t = 200 s. The same temperature is achieved at a distance of 200 mm from the dipped end at time
A. t = 283 s
B. t = 356 s
C. t = 400 s
D. t = 800 s
Answer: Option D
This Question Belongs to Chemical Engineering >> Heat Transfer
from Fouriers No.
t directly propertional to l^2
t1 / t2 =(d1 / d2)^2
t1 = 200 s
d1 = 1 m
d2 = 2 m
t2 = t1 * (d2 / d1)^2
t2 = 200 * 4 = 800 s