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BASIC NEC 2023

Battery Theory Quiz Test-1

Free online battery theory practice quiz covering lead-acid cells, primary and secondary cells, specific gravity, series/parallel connections, NiCd and Li-ion batteries, Ampere-hour capacity, C-rate, Watt-hour calculations, and battery maintenance. Ideal for electrician licence exam preparation.

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This Battery Theory Quiz Test-1 has 30 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: 30 multiple-choice, one correct answer each

30

Questions

10 min

Time

70%

Pass

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Battery Theory Quiz Test-1 — Question List

Question 1: The lead acid battery ampere hour capacity depends mainly on

quantity of electrolyte
density of electrolyte
Size of the battery container
Number of plates in the battery container

Question 2: An ideal battery should have ......................................

low internal resistance
high internal resistance
higher efficiency
none

Question 3: In the battery symbol shown in the diagram, what does the LONGER vertical line represent?

Diagram showing a single electrochemical cell symbol with long and short vertical lines

The positive terminal
The negative terminal
The internal resistance
The electrolyte level

Question 4: What is the nominal open-circuit EMF of a single fully-charged lead-acid cell?

1.5 V
2.0 V
2.4 V
6.0 V

Question 5: The electrolyte used in a lead-acid battery is:

Potassium hydroxide (KOH)
Ammonium chloride paste
Dilute sulphuric acid (H₂SO₄)
Hydrochloric acid (HCl)

Question 6: The active material on the POSITIVE plate of a fully-charged lead-acid battery is:

Sponge lead (Pb)
Lead peroxide (PbO₂)
Lead sulphate (PbSO₄)
Nickel oxide (NiO)

Question 7: The active material on the NEGATIVE plate of a fully-charged lead-acid battery is:

Lead peroxide (PbO₂)
Lead sulphate (PbSO₄)
Sponge lead (Pb)
Lead oxide (PbO)

Question 8: The specific gravity of the electrolyte in a fully-charged lead-acid battery is approximately:

1.100
1.150
1.200
1.280

Question 9: The diagram shows three 2 V cells connected in series. What is the total terminal voltage across the battery bank?

Three 2-volt electrochemical cells connected end-to-end in series

2 V
4 V
6 V
8 V

Question 10: When identical batteries are connected in PARALLEL, which quantity increases while voltage stays the same?

Voltage
Internal resistance
Ampere-hour (Ah) capacity
EMF per cell

Question 11: A PRIMARY cell differs from a SECONDARY cell in that a primary cell:

Produces a higher voltage
Cannot be recharged
Uses a liquid electrolyte
Has a lower internal resistance

Question 12: The nominal EMF of a standard zinc-carbon dry cell is approximately:

1.0 V
1.5 V
2.0 V
3.0 V

Question 13: The electrolyte in a zinc-carbon dry cell is:

Dilute sulphuric acid
Potassium hydroxide
Ammonium chloride paste
Sodium chloride solution

Question 14: During the DISCHARGE of a lead-acid battery, the specific gravity of the electrolyte:

Increases
Remains constant
Decreases
First increases then decreases

Question 15: Near full charge, a lead-acid battery "gasses." What gases are produced?

Oxygen and nitrogen
Hydrogen and oxygen
Carbon dioxide and hydrogen
Nitrogen and hydrogen

Question 16: SULFATION of a lead-acid battery is most commonly caused by:

Overcharging the battery
Leaving the battery in a discharged state for a long time
Charging at too high a current
Adding excess distilled water to the electrolyte

Question 17: What does the hydrometer in the image indicate about the battery's state of charge?

Hydrometer with the float reading at approximately 1.220 specific gravity

Fully charged (SG ≈ 1.280)
Fully discharged (SG ≈ 1.100)
Partially charged (SG ≈ 1.220)
Overcharged — electrolyte too dense

Question 18: The instrument used to measure the specific gravity of a battery electrolyte is called a:

Voltmeter
Ammeter
Hydrometer
Multimeter

Question 19: The purpose of an EQUALIZING charge on a lead-acid battery bank is to:

Fully discharge the battery before recharging
Bring all cells to an equal state of charge
Rapidly reduce the specific gravity
Remove sulfation crystals with high current

Question 20: Battery capacity is most commonly expressed in:

Volts (V)
Watts (W)
Ampere-hours (Ah)
Ohms (Ω)

Question 21: The diagram shows four identical 6 V, 100 Ah batteries wired as two series strings of two, connected in parallel (2S2P). What is the total bank voltage and capacity?

Four 6V 100Ah batteries arranged in a 2-series by 2-parallel configuration

6 V, 200 Ah
12 V, 100 Ah
12 V, 200 Ah
24 V, 100 Ah

Question 22: The electrolyte used in a nickel-cadmium (NiCd) battery is:

Dilute sulphuric acid (H₂SO₄)
Ammonium chloride paste
Potassium hydroxide (KOH)
Sodium sulphate solution

Question 23: A fully charged nickel-cadmium (NiCd) cell has a nominal voltage of approximately:

1.0 V
1.2 V
1.5 V
2.0 V

Question 24: Which rechargeable battery chemistry offers the HIGHEST energy density and is most commonly used in smartphones, laptops, and electric vehicles?

Lead-acid
Nickel-cadmium (NiCd)
Nickel-metal hydride (NiMH)
Lithium-ion (Li-ion)

Question 25: A 12 V, 100 Ah battery stores how many Watt-hours (Wh) of energy?

100 Wh
600 Wh
1,200 Wh
2,400 Wh

Question 26: A battery rated at 120 Ah is discharged at a constant current of 10 A. How long will it last (assuming ideal conditions)?

6 hours
10 hours
12 hours
120 hours

Question 27: A battery is rated 100 Ah and is being discharged at "1C." What is the discharge current?

1 A
10 A
100 A
1,000 A

Question 28: How does a decrease in temperature affect the available capacity of a lead-acid battery?

Increases
Remains the same
Decreases
First increases, then decreases

Question 29: The graph shows the discharge curve of a 12 V lead-acid battery. At which labelled point does the battery reach its recommended end-of-discharge voltage?

Graph of battery terminal voltage versus time during discharge, with points A B C D marked; a dashed line at 10.5 V marks the end-of-discharge threshold

Point A — where voltage first begins to drop
Point B — the "knee" at ~10.5 V
Point C — when voltage reaches 0 V
Point D — halfway through the discharge time

Question 30: A battery with an EMF of 12 V and an internal resistance of 0.1 Ω supplies a load current of 20 A. What is the terminal voltage?

12 V
11 V
10 V
9 V

EXAM CARD BASIC

Questions30

Time limit10 min

Pass score70%

Code editionNEC 2023

DifficultyIntermediate

Last reviewedJun 2026

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Source: NEC 2026 (NFPA 70)