1. Khi nào ta biết được chất rắn nóng chảy hoàn toàn? 2. Nếu nhiệt độ nóng chảy là xác định thì chất rắn ta xét là chất rắn kết tinh hay vô định hình. Vì sao?

Beryl states that insulation with the smallest possible thermal conductivity is best to keep a house warm in winter, but worst for keeping a house cool in summer. sapphire insists the reverse is true: low thermal conductivity is good in the summer, but bad in the winter. which one, if either is correct? a. beryl, because low thermal conductivity results in low heat transfer. b. beryl, because low thermal conductivity results in high heat transfer. d. sapphire, because low thermal conductivity results in high heat transfer. e. neither, because low heat transfer is desirable both in summer and in winter.