Lesson page
Lesson 9: Exam Practice and Common Traps
Read the lesson, then answer the multiple-choice practice set below. You get instant right or wrong feedback with explanation.
Exam Practice Japanese Vocabulary Safety and Regulations
Lesson Content
This lesson closes the loop by turning the whole course into exam practice. Review the patterns until you can recognize them quickly.
Japanese Key Term
配線用遮断器（はいせんようしゃだんき / molded case circuit breaker）
Hiragana
はいせんようしゃだんき
English Meaning
Molded case circuit breaker
Simple Explanation
The final step is learning how the exam hides easy ideas inside confusing wording.
Detailed Explanation
This lesson is a review lesson. Revisit Ohm's Law, power, circuit behavior, breaker functions, grounding, and vocabulary. Many wrong answers are built from a single confusion: wrong formula, wrong unit, wrong symbol, or wrong Japanese reading.
Key Vocabulary
- 配線用遮断器（はいせんようしゃだんき / MCCB）
- 漏電遮断器（ろうでんしゃだんき / ELCB）
- 絶縁抵抗（ぜつえんていこう / insulation resistance）
- 短絡（たんらく / short circuit）
Formula
Exam method: read, translate, identify the topic, choose the formula, calculate, and check the unit.
Worked Example
A question asks for power, but the answer choices are in watts and kilowatts. Convert before selecting the answer.
Exam Tips
Underline the verb in the question: calculate, identify, compare, or explain. The verb tells you what kind of answer is needed.
Common Exam Trap
Students often know the concept but miss the question because the Japanese term is unfamiliar. Read both the hiragana and the English meaning.
Site Reality in Japan
On site, accuracy keeps work safe and legal. The written exam trains that same habit through precise wording.
Practice Question
Which device is used for leakage protection rather than only overload protection?
Answer
ELCB
Explanation
The earth leakage circuit breaker is designed to detect leakage current and trip.
1. If the node above has no dot at crossing in exam notation, you should assume:
L ----(Node)----[SW]----(Lamp)
N ------------------------(Lamp)
Standard exam diagram logic treats crossings as non-connections unless explicit junction indication is given.
2. Most likely question theme for this hierarchy is:
DB -> Main breaker -> Branch breaker -> Lighting branch
Hierarchical protective chains are used to test protection role and branch isolation understanding.
3. A resistor is 20 ohms and the supply is 100 V. What current flows?
I = V / R = 100 / 20 = 5 A.
4. A load uses 600 W for 2 hours. How much energy is used?
0.6 kW x 2 h = 1.2 kWh.
5. Which formula gives electric power in a DC circuit?
The base power formula is P = V x I.
6. Two 30 ohm resistors are in series. What is total resistance?
Series resistance adds directly.