Based on our vast experience with EASA PART 66 examination questions and question databanks, we have prepared a practice example of questions with explanations to practice for your next exam.
Disclaimer: This questions are for training purposes only! They are in no way appearing on Suntech’s’ controlled examination sessions.
At the end of the questions you are most welcome to comment, debate and ask questions.
Module 3: Electrical Fundamentals
- Which statement accurately describes the properties of a neutron?
- A. It has no electrical charge but contributes to the atom’s mass
- B. It possesses a positive charge
- C. It has the same charge as an electron
Correct Answer: A. It has no electrical charge but contributes to the atom’s mass
Explanation: A neutron is a subatomic particle found in the nucleus of an atom. It has no net electrical charge (it is neutral) but has a mass slightly greater than that of a proton, contributing significantly to the atom’s total mass.
- What type of chemical bond results in the formation of a stable oxygen molecule (O2)?
- A. Ionic bond
- B. Covalent bond via shared electrons
- C. Protonic bond
Correct Answer: B. Covalent bond via shared electrons
Explanation: An oxygen molecule (O2) is formed through a covalent bond, where two oxygen atoms achieve stability by sharing electrons in their outer valence shells.
- An element is likely to be a good electrical conductor if its atoms have what configuration in their outermost shell?
- A. Exactly 8 valence electrons
- B. Fewer than 4 valence electrons
- C. More than 4 valence electrons
Correct Answer: B. Fewer than 4 valence electrons
Explanation: Materials with few electrons in their valence shell (1, 2, or 3) are good conductors. These valence electrons are loosely bound and can move freely as charge carriers when a voltage is applied.
- How do the electron clouds of two adjacent atoms interact with each other?
- A. They have no effect on each other
- B. They attract each other
- C. They repel each other
Correct Answer: C. They repel each other
Explanation: Electrons are negatively charged particles. According to the laws of electrostatics, like charges repel each other. Therefore, the electrons of one atom will repel the electrons of another.
- The defining characteristic of a material that is a good electrical insulator is that…
- A. its electrons are tightly bound to their parent atoms
- B. it contains a large number of free ions
- C. it has more protons than electrons
Correct Answer: A. its electrons are tightly bound to their parent atoms
Explanation: A good insulator is a material that resists the flow of electricity. This is because the electrons are held very tightly within their atomic orbits and are not free to move through the material.
- What single term is used to describe the total opposition to current in an AC circuit, encompassing both resistance and reactance?
- A. Total resistance
- B. Impedance
- C. Reactance
Correct Answer: B. Impedance
Explanation: Impedance (Z) is the measure of the total opposition that a circuit presents to an alternating current. It includes both resistance (R) and reactance (X) from inductors and capacitors.
- The operational principle of a transformer, where a changing magnetic field in one coil induces a voltage in another, is known as what?
- A. Capacitance
- B. Reactance
- C. Mutual inductance
Correct Answer: C. Mutual inductance
Explanation: A transformer works because the alternating current in the primary winding creates a changing magnetic field. This field induces a current in the secondary winding through a principle known as mutual inductance.
- A piezoelectric transducer generates an electrical signal in response to what kind of physical stimulus?
- A. Applied pressure or vibration
- B. Exposure to light
- C. Application of heat
Correct Answer: A. Applied pressure or vibration
Explanation: The piezoelectric effect is the ability of certain materials (like quartz crystals) to generate an electric charge in response to applied mechanical stress or pressure.
- What is the combined output if two 12V, 40 amp-hour batteries are wired in a parallel configuration?
- A. 12V, 80 ah
- B. 24V, 40 ah
- C. 24V, 80 ah
Correct Answer: A. 12V, 80 ah
Explanation: When batteries are connected in parallel (positive-to-positive, negative-to-negative), the voltage remains the same as one battery, but the capacities add together. So, 12V and (40 + 40) = 80 ah.
- When two identical 12V batteries are connected in parallel, what is the resulting voltage and capacity?
- A. Voltage becomes 24V, capacity is doubled
- B. Voltage remains 12V, capacity is doubled
- C. Voltage becomes 24V, capacity is unchanged
Correct Answer: B. Voltage remains 12V, capacity is doubled
Explanation: Connecting two identical batteries in parallel keeps the voltage the same (12V) but doubles the total capacity (amp-hour rating).
- Calculate the ampere-hour rating for a battery that can sustain a 30-ampere discharge for 3.5 hours.
- A. 105 ampere-hour
- B. 90 ampere-hour
- C. 30 ampere-hour
Correct Answer: A. 105 ampere-hour
Explanation: The ampere-hour (Ah) rating is calculated by multiplying the current in amperes by the time in hours. So, 30 A * 3.5 h = 105 Ah.
- If the resistance in a circuit is increased, and the voltage source remains constant, how will the current be affected?
- A. It will increase
- B. It will decrease
- C. It will remain unchanged
Correct Answer: B. It will decrease
Explanation: According to Ohm’s Law (I = V/R), current is inversely proportional to resistance. If the resistance (R) goes up and voltage (V) stays the same, the current (I) must go down.
- When the voltage applied to a fixed resistor is doubled, what is the effect on the current passing through it?
- A. The current is halved
- B. The resistance value is halved
- C. The current is doubled
Correct Answer: C. The current is doubled
Explanation: Ohm’s Law (I = V/R) states that current is directly proportional to voltage. If you double the voltage while the resistance remains constant, the current must also double.
- A parallel circuit consists of 200 lamps, each with a 400-ohm resistance, powered by a 100-volt source. What is the total current?
- A. 50 amps
- B. 40 amps
- C. 25 amps
Correct Answer: A. 50 amps
Explanation: First, find the current per lamp: I = V/R = 100V / 400? = 0.25A. Since the lamps are in parallel, the total current is the sum of the individual currents: 200 lamps * 0.25A/lamp = 50 amps.
- Calculate the combined resistance of a 4-ohm and a 6-ohm resistor wired in parallel.
- A. 2.4 ohms
- B. 24 ohms
- C. 0.24 ohms
Correct Answer: A. 2.4 ohms
Explanation: The formula for two resistors in parallel is (R1 * R2) / (R1 + R2). So, (4 * 6) / (4 + 6) = 24 / 10 = 2.4 ohms.
- For any number of resistors connected in parallel, the total equivalent resistance will always be…
- A. equal to the lowest resistor value
- B. smaller than the lowest resistor value
- C. greater than the highest resistor value
Correct Answer: B. smaller than the lowest resistor value
Explanation: When resistors are connected in parallel, the total equivalent resistance is always less than the value of the smallest individual resistor in the parallel network.
- Calculate the power consumed by a 10-ohm resistor connected to a 10V source for one minute.
- A. 100 W
- B. 10 VA
- C. 10 W
Correct Answer: C. 10 W
Explanation: Power (P) can be calculated as P = V^2 / R. So, P = (10V)^2 / 10 ohms = 100 / 10 = 10 Watts. The time duration is not needed to calculate the power.
- What safety precaution is mandatory before performing maintenance on a circuit containing a high-voltage capacitor?
- A. Confirm it is fully discharged
- B. Confirm it holds a full charge
- C. Confirm it has a residual charge
Correct Answer: A. Confirm it is fully discharged
Explanation: Capacitors can store a lethal electrical charge long after the power has been turned off. For safety, you must always ensure a high-voltage capacitor is fully discharged using an appropriate tool before you handle it.
- An electrolytic capacitor is frequently selected for applications requiring…
- A. a large physical size for a large capacitance
- B. a small physical size for low leakage
- C. a small physical size for a large capacitance
Correct Answer: C. a small physical size for a large capacitance
Explanation: Electrolytic capacitors can achieve a very high capacitance in a small package compared to other capacitor types. This makes them ideal for applications like power supply filtering where high capacitance is needed.
- If magnetic lines of flux are parallel and have the same polarity, how will they interact?
- A. They will have no effect on each other
- B. They will attract each other
- C. They will repel each other
Correct Answer: C. They will repel each other
Explanation: Magnetic lines of force that are parallel and pointing in the same direction will repel each other. This is because lines of flux can never cross and will always try to push each other apart.
