Which of the following is not true about emf of a cell?

Options

A. work calculated from it is not the maximum work obtainable from the cell
B. it is maximum voltage obtainable from the cell
C. it is the potential difference between two electrodes when no current is flowing in ciruict
D. it is responsible for the flow of steady current in the cell.

Explanation

To solve the question "Which of the following is not true about emf of a cell?", we will analyze each option provided and determine its validity based on the definition and properties of electromotive force (emf).

### Step-by-Step Solution:

1. **Understanding EMF**:
- EMF (Electromotive Force) is defined as the potential difference between two electrodes of a cell when no current is flowing in the circuit. It represents the maximum potential difference the cell can provide.

2. **Analyzing the Options**:
- **Option A**: "Work calculated from it is not the maximum work obtainable from the cell."
- This statement is **not true**. The work calculated from the EMF is indeed the maximum work obtainable from the cell under ideal conditions. Therefore, this option is incorrect.

- **Option B**: "It is the maximum voltage obtainable from the cell."
- This statement is **true**. EMF represents the maximum voltage that can be obtained from the cell when no current is flowing.

- **Option C**: "It is the potential difference between two electrodes when no current is flowing in the circuit."
- This statement is **true**. This is the definition of EMF.

- **Option D**: "It is responsible for the flow of steady current in the cell."
- This statement is **true**. EMF provides the necessary potential difference to drive a steady current through the circuit.

3. **Conclusion**:
- The only statement that is not true about EMF of a cell is **Option A**. Therefore, the answer to the question is **Option A**.

### Final Answer:
**Option A**: Work calculated from it is not the maximum work obtainable from the cell.