CameraIcon
CameraIcon
SearchIcon
MyQuestionIcon


Question

A cylindrical rod has a hot end at 70C and cold end at 30C. The rate of heat flow is 9 W. If the dimensions of the cylindrical rod are tripled keeping the temperature difference constant, then find the value of new rate of heat flow.
  1. 9 W
  2. 81 W
  3. 18 W
  4. 27 W


Solution

The correct option is D 27 W
Length of the cylindrical rod be l1
Area of cross-section of cylindrical rod be A1
Temperature difference between the ends of rod
(T1T2)=40C or 313 K
Given, Rate of heat flow (Q1)=9 W
If the dimension tripled, then
l2=3l1;A2=πr22=π(3r1)2=9(πr21)=9A1
Applying the equation of thermal conductivity
Q1Q2=(A1A2)×(l2l1)=19×3=13
Q2=3Q1=3×9=27 W

flag
 Suggest corrections
thumbs-up
 
0 Upvotes


Similar questions
View More


People also searched for
View More



footer-image