Assertion: The potential energy can be defined only in conservative field 

Reason: The value of potential energy depends on the reference level (level of zero potential energy).

The potential energy is defined as the energy possessed by an object due to its position relative to a reference level or point in a field. In conservative fields, the potential energy depends solely on the position of the object and not on the path taken to reach that position. Therefore, the value of potential energy can be uniquely determined regardless of the reference level chosen.

Assertion and reason both are true but reason is not correct explanation of assertion