下列的那些金屬是包含於焊料(solder)中?

通常，焊料（H）用嚟接合其他金屬（A和B）。理想喺在燒焊溫度，H熔A和B唔熔，所以，焊料要有低熔點。銅，鉛和鐵 的熔點分別喺１３５８，６００　和１８１１度C。明白了吧！

Lead should be the answer. The solder is an alloy which has lower melting temperature than the metals that you want to solder. Comparing the three metals, namely copper, lead and iron, lead has the lowest melting temperature of around 600C. However, teh rest two metals have the melting point over 1000C. Based on this property, lead is used as a component in the solder. Besides, other low melting metals such as tin, indium or gallium can also be used as solder. In some cases, small amount of copper is also added to the solder to improve the mechanical property of the solder.