Electrical Energy: AC/DC Systems & the Distribution Board
Electrical Energy: AC/DC Systems & the Distribution Board is one of 9 topics in the Grade 11 Agricultural 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. Which type of current flows in one direction only, at a constant polarity, and is produced by a battery?
Direct current (DC)
Alternating current (AC)
Three phase current
Earth leakage current
Answer: Direct current (DC) — Direct current (DC) flows in one direction only at a constant polarity, and is the type of current produced by a battery or solar panel.
Easy
2. At what frequency does South African AC mains supply reverse direction?
50 Hz
60 Hz
100 Hz
12 Hz
Answer: 50 Hz — South African AC mains supply oscillates at 50 Hz, meaning it reverses direction 50 times per second.
Medium
3. Name the electrical component used to efficiently step AC voltage up or down for transmission over long distances.
Answer: transformer — A transformer is used to step AC voltage up or down efficiently, which is far more difficult to achieve with DC, making AC well suited to long-distance transmission.
