Which of the following statement is false ?

Options

A. Krichhoff's second law represents energy conservation
B. Wheattstone bridge is the most sensitive when all the four resistance are of the same order of magnitude
C. In a balanced wheatstone bridge if the cell and the galvanometer are exchanged, the null point is distrubed
D. A rheostate can be used as a potential divider.

Answer

To determine which of the given statements is false, we will analyze each statement one by one.

### Step 1: Analyze Kirchhoff's Second Law
- **Statement**: Kirchhoff's second law represents energy conservation.
- **Analysis**: Kirchhoff's voltage law (KVL) states that the sum of the electrical potential differences (voltage) around any closed circuit is zero. This implies that the energy supplied by the source (like a battery) is equal to the energy consumed by the resistors in the circuit. Therefore, this statement is **true**.

### Step 2: Analyze Wheatstone Bridge Sensitivity
- **Statement**: Wheatstone bridge is most sensitive when all four resistances are of the same order of magnitude.
- **Analysis**: A Wheatstone bridge is balanced when the ratio of the two pairs of resistances is equal. When all four resistances are equal, the bridge is most sensitive to small changes in resistance, making this statement **true**.

### Step 3: Analyze the Effect of Interchanging Galvanometer and Battery
- **Statement**: In a balanced Wheatstone bridge, if the cell and the galvanometer are exchanged, the null point is disturbed.
- **Analysis**: If you interchange the galvanometer and the battery in a balanced Wheatstone bridge, the ratios of the resistances remain the same, and thus the bridge remains balanced. Therefore, the null point is not disturbed, making this statement **false**.

### Step 4: Analyze the Use of a Real State as a Potentiometer
- **Statement**: A real state can be used as a potentiometer.
- **Analysis**: A potentiometer is a device that allows for the adjustment of voltage levels. A real state (or rheostat) can indeed be used as a potentiometer to divide voltage, making this statement **true**.

### Conclusion
Based on the analysis:
- The false statement is: **In a balanced Wheatstone bridge, if the cell and the galvanometer are exchanged, the null point is disturbed.**