Question

In the Ingen Hausz's experiment, the wax melts up to lengths $10cm$ and $25cm$ on two identical rods of different materials. The ratio of thermal conductivities of the two materials is

• A. $1:6.25$
• B. $6.25:1$
• C. $1:$$\sqrt{2.5}$
• D. $1:2.5$

Answer 1

The correct option is D $1:2.5$

In the Ingen Hauszs experiment, as rate of heat transfer is constant
$\frac{K_1}{K_2}=\frac{l_1}{l_2}$
So, putting the value in above formula's we find
$\frac{K_1}{K_2}=\frac{10}{25}=\frac{1}{2.5}$