The V-I characteristics of four circuit elements are shown. Which of these is ohmic ?

Options

A.
B.
C.
D.

Answer

To determine which of the four circuit elements is ohmic based on their V-I characteristics, we need to analyze the graphs provided for each option. An ohmic element is one that follows Ohm's Law, which states that the current (I) through a conductor between two points is directly proportional to the voltage (V) across the two points. This relationship can be expressed mathematically as:

\[ V = I \cdot R \]

where R is the resistance of the conductor.

### Step-by-Step Solution:

1. **Understand Ohm's Law**:
- Recall that for an ohmic conductor, the V-I graph should be a straight line passing through the origin. This indicates that as the voltage increases, the current increases linearly.

2. **Analyze the V-I Characteristics**:
- Look at the V-I characteristics of each of the four options provided.
- Identify which graph represents a linear relationship between voltage and current.

3. **Identify the Straight Line**:
- Check each option:
- **Option 1**: If this graph is a straight line, it indicates a constant resistance and therefore is ohmic.
- **Option 2**: If this graph shows a curve, it indicates a non-linear relationship, which means it is non-ohmic.
- **Option 3**: Similarly, if this graph is curved, it is also non-ohmic.
- **Option 4**: If this graph shows a horizontal line (current is constant regardless of voltage), it is also non-ohmic.

4. **Conclusion**:
- After analyzing all four options, the only graph that represents a straight line through the origin is **Option 1**. Therefore, this option is the only one that follows Ohm's Law and is classified as an ohmic circuit.

### Final Answer:
The ohmic circuit is **Option 1**.

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