Correct Answer - A
According to problem, rate of heat loss in both rods is
equal, i.e.,`((dQ)/(dt))_(1)=((dQ)/(dt))_(2)`
`implies(K_1A_1Deltatheta_1)/(l_1)=(K_2A_2Deltatheta_2)/(l_2)`
`K_1A_1=K_2A_2[AsDeltatheta_1=Deltatheta_2=(T_1-T_2)` and `l_1=l_2` given]