The resistivity of the conductor wire depends on :

Question

Accepted Answer

The resistivity of a conductor wire is a fundamental property that is determined by specific factors. Let's explore why Option 3 is the correct answer and why the other options are incorrect.

1. **Explanation for Option 3 (Correct Answer):**
   - **Nature of Material:** The resistivity of a conductor is inherently linked to the material's atomic structure. Different materials have different numbers of free electrons available for conduction, which directly affects resistivity. For example, copper has a lower resistivity compared to iron because copper has more free electrons that can move easily.
   - **Temperature of Conductor Wire:** Resistivity is also affected by temperature. As temperature increases, the atoms in the conductor vibrate more vigorously, which can impede the flow of electrons, thereby increasing resistivity. This relationship is particularly significant in metals, where resistivity typically increases with temperature.

2. **Explanation for why other options are incorrect:**
   - **Option 1 (Length of conductor wire):** The length of the conductor wire affects resistance, not resistivity. Resistivity is an intrinsic property of the material, independent of its dimensions. While resistance increases with length, resistivity remains constant for a given material at a specific temperature.
   - **Option 2 (Cross section area of conductor wire):** Similar to length, the cross-sectional area affects resistance but not resistivity. A larger cross-sectional area allows more electrons to flow, reducing resistance, but it does not change the material's resistivity.
   - **Option 4 (Only temperature of conductor wire):** While temperature does affect resistivity, it is not the sole factor. The nature of the material is equally crucial in determining resistivity. Therefore, stating that only temperature affects resistivity is incomplete and incorrect.

In conclusion, Option 3 is the correct answer because resistivity is fundamentally dependent on both the nature of the material and the temperature of the conductor wire. The other options incorrectly attribute resistivity to factors that influence resistance or overlook the dual dependency on material and temperature.