Final answer:
A relay with Normally Open and Normally Closed contacts in a dome light circuit provides flexibility and control for turning the light on and off, depending on whether the relay is activated or not.
Step-by-step explanation:
In a dome light circuit that uses a relay with both Normally Open (NO) and Normally Closed (NC) contacts, these contacts serve specific purposes. The NO contact is used to complete the circuit when the relay is activated, thus turning on the light. The NC contact, on the other hand, ensures the circuit is completed when the relay is not activated, allowing for alternative circuit functions such as keeping the light off or connecting to another circuit.
This configuration provides flexibility in controlling the dome light as well as safeguarding against situations where the relay is not energized, ensuring the circuit can still perform a function. For example, when the vehicle door is opened, the relay may be energized to switch the dome light on using the NO contact, and when the door is closed, the dome light could remain off through the NC contact.