What type of contacts are described as equivalent to two Form B contacts in series?

The correct answer is based on the understanding of contact types in relay and control logic circuitry. Form Y contacts are indeed equivalent to two Form B contacts wired in series.

In relay logic, Form B contacts are normally closed, which means they allow current to flow through them when they are not energized. When two Form B contacts are placed in series, the entire circuit will remain closed when neither contact is activated. If either contact is opened, the circuit is interrupted.

Form Y contacts, being equivalent to two Form B contacts in series, function similarly. They are designed to ensure that the current can only flow when both conditions (represented by the two contacts) are met, thereby maintaining the integrity of the circuit.

Understanding contact types and their configurations is crucial for ensuring electrical circuits work as intended, especially in applications where multiple conditions must be satisfied for operation.