Question

A ring consisting of two parts adb and acb of same conductivity k carries an amount of heat h. The adb part is now replaced with another metal keeping the temperatures t1 and t2 constant. The heat carried increases to 2h. What should be the conductivity of the new adb part ? (given adb acb = 3) a

Answer 1

H1 + H2 = K A ( T1 - T2 ) / 3 l    +     K A ( T1 - T2 ) / l

H1 + H2 = 4 / 3l  K A ( T1 - T2 )

When it is increased to 2H:

H2 = 2 H - H1 = 7 K A ( T1 - T2 ) / 3l = K' A ( T1 - T2 ) / l

As per the values,

K' = 7 / 3 K

Conductivity of ADB part will be 7 / 3 K.