Define the term sensitivity and selectivity of a relay?

Answer: festivity and selectivity are the two main terms used in relay is a berry these are very important to understand both of these terms are discussed below

Sensitivity :
Senestivity of a relay means is its capacity to operate reliably under the actual condition that produce the least operating tendence.

Selectivity :
Selectivity means the ability to determine the point at which the fault occur and select the nearest circuit breaker in the system to trip so that the fault is cleared with minimum or no damage to the system.