Meter Bridge Applications

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What is a meter bridge?

A meter bridge is an electrical apparatus used to measure the resistance of a wire or a circuit. It is a practical application of the Wheatstone bridge circuit.

How does a meter bridge help determine unknown resistance?

A meter bridge calculates unknown resistance with the formula: \( R_x = \frac{R_2L_1}{100 - L_1} \), where \( L_1 \) is the balance length at which the bridge is balanced.

What role does the jockey play in meter bridge applications?

The jockey is a movable contact that the user slides along the wire to achieve a balanced meter bridge, indicated by zero deflection on the galvanometer.

Why is it important for the wire in a meter bridge to have uniform cross-sectional area?

Uniform cross-section ensures that the wire has consistent resistance per unit length, which is vital for accurate measurements.

What is the principle behind a meter bridge?

The meter bridge operates on the principle of Wheatstone bridge circuit balancing, which ensures that the ratio of two resistances is equal to the ratio of two lengths in the circuit.

What are some common errors in meter bridge experiments?

Errors can arise from contact resistance, non-uniform wire, or incorrect length measurements. Regular calibration can help reduce these errors.

Can a meter bridge measure very high resistances accurately?

No, a meter bridge is typically used for measuring moderate to low resistance. For very high resistances, a Megger is more appropriate.

How does temperature affect measurements taken using a meter bridge?

Temperature can affect the resistance of the wire and components used in the meter bridge, leading to potential errors if not accounted for.

What is the significance of the length of the wire in a meter bridge?

The one-meter length of the wire is fundamental for achieving a balanced bridge and simplifies calculation, providing a direct ratio for resistance measurements.

What is 'null point' in the context of a meter bridge?

The null point is the position on the meter bridge wire where the galvanometer shows zero deflection, indicating that the bridge is balanced.

Why is a meter bridge typically made using a wooden base?

A wooden base is used to avoid any electrical interference, providing insulation and stability during measurements.

What materials are commonly used for the wire in the meter bridge?

Nichrome or constantan are commonly used because they provide uniform resistance and minimal temperature dependency.

How can a meter bridge be used to find the specific resistance of a wire?

Specific resistance can be found by determining the resistance of the wire using the bridge and applying the formula \( \rho = R\cdot\frac{A}{L} \), where \( R \) is resistance, \( A \) is cross-sectional area, and \( L \) is length.

What are alternative applications of a meter bridge beyond measuring resistance?

Besides measuring unknown resistances, meter bridges can also test conductivity of solutions when connected with appropriate electrodes.

How does a meter bridge illustrate Ohm’s Law?

A meter bridge illustrates Ohm's Law when used to measure resistance, which is derived from the potential difference and current flowing through the wire according to \( V = IR \).

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