Which of the following obey's Ohm's law?

Options

A. Transistor
B. Nichrome
C. Diode
D. Liquid electrolyte

Explanation

To determine which of the following materials obeys Ohm's law, we first need to understand the definition of Ohm's law and the characteristics of materials that follow it.

### Step-by-Step Solution:

1. **Understand Ohm's Law**:
Ohm's law states that the current (I) flowing through a conductor between two points is directly proportional to the voltage (V) across the two points. This can be expressed mathematically as:
\[ V = I \cdot R \]
where \( R \) is the resistance of the conductor.

2. **Identify Linear Relationship**:
For a material to obey Ohm's law, the relationship between voltage and current must be linear. This means that if you plot a graph of voltage (V) against current (I), it should yield a straight line passing through the origin.

3. **Examine the Materials**:
- **Conductors**: Materials like copper and nichrome are typically good conductors and often obey Ohm's law under normal conditions.
- **Diodes**: These are semiconductor devices that do not have a linear relationship between voltage and current. They exhibit a non-linear I-V characteristic.
- **Transistors**: These are also semiconductor devices and do not obey Ohm's law in a linear manner.

4. **Conclusion**:
Based on the characteristics of the materials, nichrome wire is a good example of a conductor that obeys Ohm's law because it maintains a linear relationship between voltage and current.

### Final Answer:
The material that obeys Ohm's law is **nichrome wire**.