The two rods show in figure have identical geometrical dimension.. They are in contact with two heat baths at temperature `100^(@)C` . And `0^(@)C` . The temperature of the junction is `70^(@)C` . Find the temperature of the junction if the rods are interchanged.

Answer

C

Explanation

Now ,Q/t remains same in both cases`
In case I,(K_AxxAxx(100-70))/l`
`(K_B xxAxx(70-0))/l`
`implies30K_A=70K_B`
`In case II,(K_(B)xxA xx(100-theta))/l`
`(K_(B)xxA xx(theta-0))/l`
`implies100K_B-K_B theta =K_A theta`
`implies100K_B-K_B theta =(70/30)K_Bxxtheta`
`implies 100=7/3 theta+theta`
`implies 100=(10/3)theta`
`implies theta=(300/10)=30^(@)C.`