Properties of Semiconductors: Practice Problem & Solution

Solution Explained:

To solve this problem, we apply the core principles of Properties of Semiconductors. Understanding the underlying formula is key to arriving at the correct answer below:

Both N-type and P-type germanium are electrically neutral because, while they have an imbalance of charge carriers (electrons or holes), the overall number of positive and negative charges remains equal.

- **N-type**: Donor atoms add extra electrons (negatively charged carriers), but the atoms themselves become positively charged ions. This ensures charge neutrality.

- **P-type**: Acceptor atoms create holes (positively charged carriers) by accepting electrons, but the atoms become negatively charged ions. This balances the charge.

In both cases, the total positive and negative charges cancel each other out, keeping the material electrically neutral.