The correct answer is: C. increase its electrical conductivity.
Suitable impurities are added to a semiconductor depending on its use. This is done in order to increase its electrical conductivity. The impurities are called dopants, and they can either increase or decrease the conductivity of the semiconductor.
Dopants that increase the conductivity are called donors. They donate electrons to the semiconductor, which makes it more conductive. Dopants that decrease the conductivity are called acceptors. They accept electrons from the semiconductor, which makes it less conductive.
The type of dopant that is used depends on the desired application of the semiconductor. For example, semiconductors that are used in transistors need to have a high conductivity, so they are doped with donors. Semiconductors that are used in solar cells need to have a low conductivity, so they are doped with acceptors.
Here is a brief explanation of each option:
- A. increase its life: This is not the main reason why impurities are added to semiconductors. The main reason is to increase their electrical conductivity. However, impurities can also affect the life of a semiconductor. For example, impurities can cause the semiconductor to degrade over time.
- B. enable it to withstand higher voltages: This is not the main reason why impurities are added to semiconductors. The main reason is to increase their electrical conductivity. However, impurities can also affect the ability of a semiconductor to withstand high voltages. For example, impurities can make a semiconductor more susceptible to breakdown.
- D. increase its electrical resistivity: This is not the main reason why impurities are added to semiconductors. The main reason is to increase their electrical conductivity. However, impurities can also affect the electrical resistivity of a semiconductor. For example, impurities can make a semiconductor more resistant to current flow.