d
We know that the rate of flow of heat is proportional to temperature difference between two ends. So
$\frac{{dQ}}{{dt}} \propto \left( {{T_2} - {T_1}} \right)$
$\frac{{dQ}}{{dt}} = k\left( {{T_2} - {T_1}} \right)$
$\frac{{d{Q_1}}}{{dt}} = k\left[ {110 - 100} \right] = k \times 10$
$\frac{{d{Q_2}}}{{dt}} = k \times 10$
$\frac{{d{Q_1}}}{{dt}} = \frac{{d{Q_2}}}{{dt}} = 4.0\,\,J/s$