Question

Two identical conducting rods are first connected independently to two vessels, one containing water at `100^@C` and the other containing ice at `0^@C`. In the second case, the rods are joined end to end and connected to the same vessels. Let `q_1 and q_2` gram per second be the rate of melting of ice in the two cases respectively. The ratio `q_1/q_2` is
(a) `1/2` (b)`2/1` (c)`4/1` (d)`1/4`
A. `1/2`
B. `2/1`
C. `4/1`
D. `1/4`

Answer 1

Correct Answer - C
Initially the rods are placed in vessels as shown below

`(Q)/(t) = ((theta_(1)-theta_(2)))/(R) rArr (Q/t)_(1) = (mL)/(t) = q_(1)L=((100-0))/((R)/(2))` ..(i)
Finally when rods are joined end to as shown

`rArr (Q/t)_(2) = (mL)/(t) = q_(2)L = ((100-0))/(2R)` ..(ii)
Form equation (i) and (ii) , `(q_1)/(q_2) = 4/1`.