Question

Which of the following statements is/are incorrect for a meter bridge, which is used to compare two resistances?

• A. If its wire is replaced by another wire having same length, made of same material but having twice the cross sectional area, the accuracy increases.
• B. If its wire is replaced by another wire of different material, having same cross sectional area but of twice the length, accuracy increases.
• C. If its wire is replaced by another wire of same material, having half the cross sectional radius and half the length, accuracy decreases but sensitivity increases
• D. Metre bridge works on the principle of Wheat-stone bridge.

Answer 1

The correct option is A If its wire is replaced by another wire having same length, made of same material but having twice the cross sectional area, the accuracy increases.

The Meter Bridge works on the principle of Wheatstone bridge. The accuracy would depend on the fact that how precisely we find out the balance length. As we find the balancing length manually , the accuracy would increase if the voltage variation along the length decreases so that the balancing length is larger and the relative uncertainty associated to it is less. Changing the area won't affect the accuracy much. However, it certainly would affect the sensitivity of meter bridge.