The potential difference across the terminals of the cell in open circuit is called as

Options

A. current
B. pot. diff. of cell
C. e.m.f. of cell
D. resistance

Answer

To solve the question, "The potential difference across the terminals of the cell in open circuit is called as," we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Open Circuit**:
- An open circuit is a circuit where the current does not flow because the circuit is not complete. This means that there is a break in the circuit.

2. **Identifying Terms**:
- In the context of a cell, we have several important terms:
- \( E \): Electromotive Force (EMF) of the cell.
- \( V \): Potential difference across the terminals of the cell.
- \( I \): Current flowing through the circuit.
- \( r \): Internal resistance of the cell.

3. **Applying the Formula**:
- The relationship between these terms can be expressed with the formula:
\[ E - V = I \cdot r \]
- In an open circuit, the current \( I \) is equal to zero because there is no complete path for the current to flow.

4. **Substituting Values**:
- Since \( I = 0 \) in an open circuit, we can substitute this into the formula:
\[ E - V = 0 \cdot r \]
- This simplifies to:
\[ E - V = 0 \]

5. **Conclusion**:
- From the above equation, we can conclude that:
\[ E = V \]
- Therefore, the potential difference across the terminals of the cell in an open circuit is equal to the EMF of the cell.

6. **Final Answer**:
- The potential difference across the terminals of the cell in an open circuit is called **Electromotive Force (EMF)**.