Question 1: What happens when a DC supply is supplied to Primary of a transformer?
- A small current flows in primary
- Core losses will increase
- Leakage reactance is increased
- Primary winding may burn out
BASIC
NEC 2023
Transformer Practice Quiz Test-1
Free Online Quiz test transformer theory and practice.
How this test works
Read each question carefully
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How to Use This Practice Test
This Transformer Practice Quiz Test-1 has 10 questions with detailed answers and NEC references. Take the full test, review every wrong answer, and look up the NEC article it references before moving on.
Tip: Work through Ohm's Law problems on paper — don't just read the answers, calculate them yourself.
- Topics covered: Voltage, current, resistance, Ohm's Law, series/parallel circuits, and electrical safety.
- Passing score: Aim for 90%+ on basic theory — these fundamentals underpin every advanced topic.
- Questions: 10 multiple-choice, one correct answer each
10
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15 min
Time
70%
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TimeTransformer Practice Quiz Test-1 — Question List
Question 2: <span style="color: #000000;">A transformer has an efficiency of 90% which works at 120 V, 3.6 kW. If the secondary voltage is 240 Volts, what is the primary current? </span>
- 40 amperes
- 20 amperes
- 30 amperes
- 50 amperes
Question 3: A transformer having 1500 turns in primary winding 300 turns in secondary winding is supplied with 120 volts AC. What is its secondary Voltage?
- 24 Volts
- 48 Volts
- 12 Volts
- 60 Volts
Question 4: A three-phase 4 wire electrical system phase-phase voltage is 480 volts. what is its phase to neutral voltage?
- 377 volts
- 277 volts
- 480 volts
- 240 volts
Question 5: The Scott connection is used to change three phase power into two phase power.
- True
- False
Question 6: What is the phase angle between primary and secondary of a transformer?
- 180 degrees
- 90 degrees
- 270 degrees
- 360 degrees
Question 7: The ampere current in primary side of a transformer is directly proportional to ampere current in secondary.
- True
- False
Question 8: What is the best way to connect to single phase transformers to act as three phase transformer?
- open-delta
- Scott connection
- deltas-star
- none
Question 9: Transformer is laminated to reduce .....................
- eddy current losses
- hysteresis losses
- both eddy current and hysteresis losses
- None
Question 10: The Transformer is not used in DC Power supply system because
- high losses will occur
- There is no need of step up of dc power supply
- the rate of change of flux is zero
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