Teaching BPSC 4.0 बिहार उच्च माध्यमिक शिक्षक भर्ती (PGT) Mock Test Physics Thermal Properties of Matter Heat transfer
Two rods whose lengths are l1 and l2 with heat conductivity coefficients k1 and k2 are placed end to end. The heat conductivity coefficient of a uniform rod of length l1 + l2 whose conductivity is same as that of the system of these two rods is
1
\(\frac{\left(l_{1}+l_{2}\right) k_{1} k_{2}}{k_{2} l_{1}+k_{1} l_{2}}\)
2
\(\frac{\left(l_{1}+l_{2}\right) k_{1} k_{2}}{k_{1} l_{1}+k_{2} l_{2}}\)
3
\(\frac{k_{1} l_{1}+k_{2} l_{2}}{\left(l_{1}+l_{2}\right) k_{1} k_{2}}\)
4
More than one of the above
5
None of the above