Statement I: Two solid cylindrical rods of identical size and different thermal conductivity `K_1` and `K_2` are connected in series. Then the equivalent thermal conductivity of two rods system is less than that value of thermal conductivity of either rod.
Statement II: For two cylindrical rods of identical size and different thermal conductivity `K_1` and `K_2` connected in series, the equivalent thermal conductivity K is given by `(2)/(K)=(1)/(K_1)+(1)/(K_2)`

Options

A. Statement I is true, Statement II is true and Statement II is the correct explanation for statement I.
B. Statement I is true, statement II is true and statement II NOT the correct explanation for Statement I
C. Statement I is true, Statement II is false.
D. Statement I is false, statement II is true.

Answer

D

Explanation

Equivalent thermal conductivity of two identical rods in series is given by
`(2)/(K)=(1)/(K_1)+(1)/(K_2)`
If `K_1ltK_2`, then `K_1ltKltK_2`. Hence statement I is false.