Two identical conducting rods are first connected independently to two vessels, one containing water at 100^oC and the other containing ice at 0^oC. In the second case, the rods are joined end to end and connected to the same vessels. Let q₁ and q₂g/s be the rate of melting of ice in two cases, respectively. The ratio of q₁/q₂ is

detailed solution

Correct option is C

Initially the rods are placed in vessels as shown below.Qt=θ1−θ2R⇒Qt1=mLt=q1L=(100−0)R2  …..(i)Finally when rods are joined end to end as shown,⇒Qt2=mLt=q2L=(100−0)2R  ……..(ii)From equations (i) and (ii), q1q2=41IN series combination thermal resistance is four times to that in parallel combination of identical conducting rods .so in parallel combination heat flow is 4 times and hence rate of melting of ice will be 4 times to that in parallel combination.