Electronics - Semiconductor Principles - Discussion

Please any one help me with the relation between coal ash and germanium!

But coal consists of carbon right. Then?

I think graphite would have been a better option. It is an element of carbon family. Correct. ?

Coal consists of carbon, then how can we say its germanium?

Though, graphite belongs to carbon family, but the first preference goes to carbon I think.

Coal ash consists of carbon.

I too agree with you @Shwetha and @Reena.

Of course the coal consists of carbon. How could it be graphite?

Silicon:

Silicon is the second most abundant element on earth, making up almost over 25% of the earth's crust by weight. Although not found as a free element in nature, it occurs as oxide and silicates including agate, amethyst, citrine, jasper, flint, opal, quartz, and sand. Silicon metal is derived from reactions between silicon dioxide and carbon materials like coke, coal and wood chips.

In terms of the major producers of silicon for wafers, there are many suppliers in the US and around the world, primarily in California, Oregon, Florida, Asia-Pacific, China, and Europe. It is believed that China is the largest producer of silicon, followed by the United States.

Germanium:

Germanium is a chemical element that is similar in appearance to silicon, and not found as a free element in nature because of its reactivity factor. Available in the earth's crust, it is mined from sphalerite zinc ores and can also be extracted from fly ash coal and copper ores. Germanium is less useful than silicon due to its thermal sensitivity and cost, but it is still alloyed with silicon for use in some high-speed devices. IBM is a primary producer of these devices. The leader in germanium production is China, with the other major producers including the USA, Canada, Russia, and Belgium.

So what that mean? I guess answer is carbon because there is no connection between germanium and carbon.

Germanium is mined from sphalerite zinc ores and can also be extracted from fly ash coal and copper ores.

So Ge is the best answer because in Question he is talking about semiconductor not insulators or conductors, Graphite which is a shape of carbon but act like a conductor not semiconductor so Carbon is not correct answer so Ge is best and correct answer.