21. 瓷釉藥實驗常使用如下圖的三角座標法,其黑點所在位置的 A 含量百分比是多少? (A) 60% (B) 50% (C) 30% (D) 10%
5. The capacitors of Fig. 5 are uncharged. The switch is closed at t = 0 s for 8 ms.