Forging meter bridge practicals.

To forge a meter bridge, you will need the following materials:

- Two resistors of known values (e.g. 100 ohms and 200 ohms)
- A galvanometer
- A battery or power supply
- Connecting wires
- A meter bridge wire

Here is a step-by-step guide to forging a meter bridge:

1. Set up the meter bridge by connecting the two resistors in series on one side of the bridge wire. Connect the galvanometer in parallel with one of the resistors.

2. Connect the battery or power supply to the other side of the bridge wire.

3. Adjust the position of the galvanometer until it reads zero (balanced condition).

4. Measure the lengths of the bridge wire on each side of the galvanometer.

5. Use the formula L1/R1 = L2/R2 to calculate the unknown resistance R2.

6. Verify the calculated resistance by connecting a known resistor in place of the unknown resistor and adjusting the position of the galvanometer to zero.

7. Repeat the process with different combinations of resistors to practice forging different meter bridge configurations.

By following these steps, you can practice forging meter bridge configurations and gain a better understanding of how to measure unknown resistances using a meter bridge.

Objective:

To determine the unknown resistance of a conductor using a meter bridge.

Materials:

- Meter bridge
- Resistor box (10Ω to 10kΩ)
- Jockey
- Unknown resistor
- Connecting wires
- Battery
- Key

Procedure:

1. Set up the meter bridge: Connect the battery, key, resistor box, and unknown resistor to the meter bridge as shown in the diagram below.


2. Balance the bridge:
- Close the key and adjust the jockey until the galvanometer shows zero deflection.
- At this point, the bridge is balanced, and the unknown resistance (R) is given by:

```
R = (L1 / L2) - S
```

where:
- L1 is the length of the wire from the left end of the bridge to the jockey
- L2 is the length of the wire from the jockey to the right end of the bridge
- S is the known resistance of the resistor box

3. Measure L1 and L2:
- Use a ruler to measure the distance between the left end of the bridge and the jockey (L1).
- Similarly, measure the distance between the jockey and the right end of the bridge (L2).

4. Calculate the unknown resistance:
- Substitute the values of L1, L2, and S into the formula given in step 2 to calculate the unknown resistance (R).

Sample Calculations:

If the following measurements are obtained:

- L1 = 30 cm
- L2 = 70 cm
- S = 100 Ω

Then, the unknown resistance is:

```
R = (L1 / L2) - S
= (30 cm / 70 cm) - 100 Ω
= 42.86 Ω
```

Precautions:

- Ensure that the battery is in good condition and provides a constant voltage.
- Handle the galvanometer with care to avoid damage.
- Make sure that the connections are tight and secure.