An iron bar (L1 = 0 1 m, A1= 0 02 m2 , K1 = 80 W m 1 K - Physics - Mechanical Properties Of Solids

Question

An iron bar (L1 = 0 1 m, A1= 0 02 m2
, K1 = 80 W m?1 K?1) and a brass bar (L2 = 0 1 m, A2 = 0 02
m2
, K2 = 120 W m?1K?1) are soldered end to end The free ends of the
iron bar and brass bar are
maintained at 400K and 300 K respectively What is the the
temperature of the junction of the two
bars?

Vipra Mishra · Accepted Answer

Solution
Let emperature of the junction be T0
 As both the bars are connected in series so heat current through them is equal 
Heat current through iron rod =KironAiron(T1-T)L1 =KironAiron(400-T)0
1=80×0 02(400-T)0
1Heat current through brass rod =KbrassAbrass(T-T2)L2=KbrassAbrass(T-300)0
1=120×0 02×(T-300)0 1So80×0 02(400-T)0
1 =120×0 02×(T-300)0
180(400-T) =120(T-300)(400-T)(T-300)=12080=1 5400- T=1
5 T-450950= 2 5 TT =380 K

An iron bar (L1 = 0.1 m, A1= 0.02 m2 , K1 = 80 W m?1 K?1) and a brass bar (L2 = 0.1 m, A2 = 0.02 m2 , K2 = 120 W m?1K?1) are soldered end to end. The free ends of the iron bar and brass bar are maintained at 400K and 300 K respectively. What is the the temperature of the junction of the two bars?

An iron bar (L1 = 0.1 m, A1= 0.02 m2
, K1 = 80 W m?1 K?1) and a brass bar (L2 = 0.1 m, A2 = 0.02
m2
, K2 = 120 W m?1K?1) are soldered end to end. The free ends of the iron bar and brass bar are
maintained at 400K and 300 K respectively. What is the the temperature of the junction of the two
bars?