Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A): For the most precise measurement of an unknown resistance using a Wheatstone bridge, the ratio arms should be small and approximately equal to each other. Reason (R): Small and equal ratio arms ensure a large galvanometer deflection even for a very small unbalance in the bridge circuit. In the ligh

Step-by-step solution

Assertion (A) states that for precise measurement, the ratio arms should be small and approximately equal. This is correct because the sensitivity of a Wheatstone bridge is maximum when all four arms have resistances of the same order of magnitude. Furthermore, smaller overall resistances allow a larger current to flow from the battery. Reason (R) states that this ensures a large galvanometer deflection for a small unbalance. This is also correct. The precision of the measurement depends on how easily a slight unba