Question

What is the advantage of using metre bridge for finding unknown resistance?

Answer 1

Advantages of using Wheat stone bridge are :

1. To find the unknown resistance very very accurately.

2.As this method does not involve direct measurement of current or voltage

directly with ammeter or voltmeter . so resistance offered by ammeter and voltmeter do not effect the readings .

3. )it shows a null measurement(i.e.-potential

difference across the end points of the bridge is zero)

Answer 2

Any current drain from the circuit will affect the measured value.

At balance a meter bridge draws no current.

However modern voltmeters have a VERY high input resistance, so the limited accuracy of measurement with a meter bridge (1mm in 1m or 0.1%) becomes more significant.

When the bridge is balanced, zero current is flowing through the resistor, eliminating errors of voltage drop across connections, or due to heating.