Relays, Solenoids & Intro to the DC Motor is one of 9 topics in the Grade 10 Electrical Technology CAPS syllabus, covered across 3 lessons on Study Vault. Below are real practice questions from this topic with full worked answers.
Sample practice questions
Easy
1. What is a relay, fundamentally?
An electromagnetically operated switch
A component that stores electrical charge
A component used only to limit current flow
A type of resistor with an adjustable value
Answer: An electromagnetically operated switch — A relay is an electromagnetically operated switch: a control current energises a coil, which attracts an armature, which mechanically operates a separate set of switch contacts.
Easy
2. What does a normally open (NO) relay contact do when the coil is de-energised?
It remains open (not making a connection)
It remains closed (making a connection)
It oscillates rapidly between open and closed
It is permanently welded closed regardless of coil state
Answer: It remains open (not making a connection) — A normally open (NO) contact is open (not making a connection) when the coil is de-energised, and only closes when the coil is energised.
Medium
3. Name the movable, spring-loaded part of a relay that physically moves when the coil is energised, mechanically operating the switch contacts.
Answer: armature — The armature is the movable, spring-loaded part of a relay that physically moves when the coil is energised, mechanically operating the switch contacts.
