Heat flows radially outward through a spherical shell of outside radius 3R and inner radius R. The temperature of inner surface of shell is θ1 and that of outer is θ2. The radial distance from centre of shell where the temperature is just half way between θ1 and θ2 is
(A)2R
(B)3R
(C)3R/2
(D)5R/2
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5 Answers
1Hi Akhil
Would you like to show me?I used the conduction formula but I did not get the answer.
Hi jeetopper
How can b be the right answer.As it is the radius of the bigger shell.And it has been given that the outer surface of the bigger shell is theta2.So at a distance of 3R the temperature is theta2.Please try the problem once again.
11sorry c is the answer.
basically what you do is consider a shell of radius r and thickness dr
then dQ/dt=K4∩r2d∂/dr
∫hdr/r2=∫4∩Kd∂
now integrat first R→3R n ∂1→∂2..................1
then R→x n ∂1→∂1+∂2/2.....................2
divide i by 2 to get x