Heat and Thermodynamics

Two identical plates P and Q , radiating as perfect black bodies, are kept in vacuum at constant absolute temperatures Tp and TQ, respectively, with TQ<TP, as shown in Fig. 1. The radiated power transferred per unit area from P to Q is W0. Subsequently, two more plates, identical to P and Q , are introduced between P and Q , as shown in Fig. 2. Assume that heat transfer takes place only between adjacent plates. If the power transferred per unit area in the direction from P to Q (Fig. 2) in the steady state is Ws, then the ratio ‌

W0

Ws

is ____