Which of the following is correct statement

Options

A. silicon doped with boron is n-type semiconductor
B. silicon doped with arsenic is a p-type semiconductor
C. metals are good conductors of electricity
D. electrical conductivity of semiconductors decreases with increasing temperature

Answer

To determine which of the given statements is correct, let's analyze each statement one by one:

### Step 1: Analyze the First Statement
**Statement:** Silicon doped with boron is an n-type semiconductor.

- **Explanation:** Silicon (Si) belongs to Group 14 and has 4 valence electrons. When silicon is doped with boron (B), which is a trivalent element (Group 13) with 3 valence electrons, it forms covalent bonds with silicon atoms. Since boron has one less electron than silicon, it creates a "hole" in the structure, which is a positive charge carrier. Thus, silicon doped with boron is a **p-type semiconductor**, not n-type.

**Conclusion:** This statement is **incorrect**.

### Step 2: Analyze the Second Statement
**Statement:** Silicon doped with arsenic is a p-type semiconductor.

- **Explanation:** Arsenic (As) is a pentavalent element (Group 15) with 5 valence electrons. When silicon is doped with arsenic, the arsenic atom shares its 4 electrons with the silicon atoms, leaving one extra electron free. This extra electron contributes to electrical conduction, making it an **n-type semiconductor**.

**Conclusion:** This statement is **incorrect**.

### Step 3: Analyze the Third Statement
**Statement:** Metals are good conductors of electricity.

- **Explanation:** Metals have a structure that allows for free movement of electrons. They possess low ionization energy, which means that at room temperature, valence electrons can easily be freed from their atoms. These free electrons can move through the metal lattice, allowing metals to conduct electricity effectively.

**Conclusion:** This statement is **correct**.

### Step 4: Analyze the Fourth Statement
**Statement:** Electrical conductivity of semiconductors decreases with increasing temperature.

- **Explanation:** In semiconductors, as temperature increases, thermal energy allows more electrons to jump from the valence band to the conduction band. This results in an increase in the number of charge carriers, thereby increasing the electrical conductivity. Therefore, the conductivity of semiconductors actually **increases** with temperature.

**Conclusion:** This statement is **incorrect**.

### Final Conclusion
After analyzing all the statements, we find that the only correct statement is:

**Metals are good conductors of electricity.**