TKT AT&T TECHNICAL KNOWLEDGE TEST – ELECTRICAL CURRENT &
OHM'S LAW | 300 QUESTIONS & VERIFIED ANSWERS | GUARANTEED PASS
2026
TKT – Technical Knowledge Test
Electrical Current & Ohm's Law Review
1. What is electrical current?
Answer: Electrical current is the flow of electric charge (electrons) through a
conductor, measured in amperes (A).
2. What is the SI unit of electrical current?
Answer: The ampere (A), often called 'amp.'
3. What is conventional current direction?
Answer: Conventional current flows from positive (+) to negative (−), opposite to
the actual flow of electrons.
4. What is electron flow direction?
Answer: Electrons flow from negative (−) to positive (+).
5. What is direct current (DC)?
Answer: Direct current is electrical current that flows in one constant direction.
6. What is alternating current (AC)?
Answer: Alternating current periodically reverses direction, typically at 60 Hz in
the US.
7. Define a coulomb.
Answer: A coulomb is the SI unit of electric charge; 1 ampere equals 1 coulomb
of charge passing a point per second.
8. What is the formula relating current, charge, and time?
,Answer: I = Q / t, where I = current (A), Q = charge (coulombs), t = time
(seconds).
9. How many electrons make up 1 coulomb of charge?
Answer: Approximately 6.242 × 10¹⁸ electrons.
10. What is a conductor?
Answer: A material that allows electrons to flow freely; examples include copper,
aluminum, and silver.
11. What is an insulator?
Answer: A material that resists the flow of electrons; examples include rubber,
plastic, and glass.
12. What is a semiconductor?
Answer: A material with conductivity between conductors and insulators;
examples include silicon and germanium.
13. What drives current through a circuit?
Answer: Voltage (electromotive force) drives current through a circuit.
14. What opposes the flow of current?
Answer: Resistance opposes the flow of current.
15. What instrument measures current?
Answer: An ammeter measures current. It is connected in series with the circuit.
16. How is an ammeter connected in a circuit?
Answer: In series with the load, so all current flows through it.
17. What is the symbol for current in formulas?
Answer: The letter I (from the French word 'intensité').
18. What is milliampere (mA)?
Answer: One-thousandth of an ampere; 1 mA = 0.001 A.
19. What is microampere (μA)?
Answer: One-millionth of an ampere; 1 μA = 0.000001 A.
20. What is a closed circuit?
Answer: A complete, unbroken path through which current can flow.
21. What is an open circuit?
Answer: A break in the circuit path that stops current flow.
22. What is a short circuit?
, Answer: An unintended low-resistance path that allows excessive current to
flow, bypassing the load.
23. What is current density?
Answer: Current per unit cross-sectional area of a conductor, measured in A/m².
24. What happens to current if voltage doubles (resistance constant)?
Answer: Current doubles (directly proportional to voltage per Ohm's Law).
25. What happens to current if resistance doubles (voltage constant)?
Answer: Current halves (inversely proportional to resistance per Ohm's Law).
26. What is drift velocity?
Answer: The average velocity of electrons moving through a conductor due to
an electric field, typically very slow (mm/s).
27. What is the difference between DC and AC current?
Answer: DC flows in one direction; AC periodically reverses direction at a set
frequency.
28. What are common sources of DC?
Answer: Batteries, solar cells, and DC power supplies.
29. What are common sources of AC?
Answer: Wall outlets, generators, and transformers.
30. What is the frequency of AC power in the United States?
Answer: 60 Hz (60 cycles per second).
Section 2: Voltage (Q31–60)
31. What is voltage?
Answer: Voltage is the electrical potential difference between two points,
measured in volts (V).
32. What is the SI unit of voltage?
Answer: The volt (V).
33. What instrument measures voltage?
Answer: A voltmeter measures voltage. It is connected in parallel with the
component.
34. How is a voltmeter connected?
Answer: In parallel across the component or circuit being measured.
35. What is EMF (electromotive force)?
OHM'S LAW | 300 QUESTIONS & VERIFIED ANSWERS | GUARANTEED PASS
2026
TKT – Technical Knowledge Test
Electrical Current & Ohm's Law Review
1. What is electrical current?
Answer: Electrical current is the flow of electric charge (electrons) through a
conductor, measured in amperes (A).
2. What is the SI unit of electrical current?
Answer: The ampere (A), often called 'amp.'
3. What is conventional current direction?
Answer: Conventional current flows from positive (+) to negative (−), opposite to
the actual flow of electrons.
4. What is electron flow direction?
Answer: Electrons flow from negative (−) to positive (+).
5. What is direct current (DC)?
Answer: Direct current is electrical current that flows in one constant direction.
6. What is alternating current (AC)?
Answer: Alternating current periodically reverses direction, typically at 60 Hz in
the US.
7. Define a coulomb.
Answer: A coulomb is the SI unit of electric charge; 1 ampere equals 1 coulomb
of charge passing a point per second.
8. What is the formula relating current, charge, and time?
,Answer: I = Q / t, where I = current (A), Q = charge (coulombs), t = time
(seconds).
9. How many electrons make up 1 coulomb of charge?
Answer: Approximately 6.242 × 10¹⁸ electrons.
10. What is a conductor?
Answer: A material that allows electrons to flow freely; examples include copper,
aluminum, and silver.
11. What is an insulator?
Answer: A material that resists the flow of electrons; examples include rubber,
plastic, and glass.
12. What is a semiconductor?
Answer: A material with conductivity between conductors and insulators;
examples include silicon and germanium.
13. What drives current through a circuit?
Answer: Voltage (electromotive force) drives current through a circuit.
14. What opposes the flow of current?
Answer: Resistance opposes the flow of current.
15. What instrument measures current?
Answer: An ammeter measures current. It is connected in series with the circuit.
16. How is an ammeter connected in a circuit?
Answer: In series with the load, so all current flows through it.
17. What is the symbol for current in formulas?
Answer: The letter I (from the French word 'intensité').
18. What is milliampere (mA)?
Answer: One-thousandth of an ampere; 1 mA = 0.001 A.
19. What is microampere (μA)?
Answer: One-millionth of an ampere; 1 μA = 0.000001 A.
20. What is a closed circuit?
Answer: A complete, unbroken path through which current can flow.
21. What is an open circuit?
Answer: A break in the circuit path that stops current flow.
22. What is a short circuit?
, Answer: An unintended low-resistance path that allows excessive current to
flow, bypassing the load.
23. What is current density?
Answer: Current per unit cross-sectional area of a conductor, measured in A/m².
24. What happens to current if voltage doubles (resistance constant)?
Answer: Current doubles (directly proportional to voltage per Ohm's Law).
25. What happens to current if resistance doubles (voltage constant)?
Answer: Current halves (inversely proportional to resistance per Ohm's Law).
26. What is drift velocity?
Answer: The average velocity of electrons moving through a conductor due to
an electric field, typically very slow (mm/s).
27. What is the difference between DC and AC current?
Answer: DC flows in one direction; AC periodically reverses direction at a set
frequency.
28. What are common sources of DC?
Answer: Batteries, solar cells, and DC power supplies.
29. What are common sources of AC?
Answer: Wall outlets, generators, and transformers.
30. What is the frequency of AC power in the United States?
Answer: 60 Hz (60 cycles per second).
Section 2: Voltage (Q31–60)
31. What is voltage?
Answer: Voltage is the electrical potential difference between two points,
measured in volts (V).
32. What is the SI unit of voltage?
Answer: The volt (V).
33. What instrument measures voltage?
Answer: A voltmeter measures voltage. It is connected in parallel with the
component.
34. How is a voltmeter connected?
Answer: In parallel across the component or circuit being measured.
35. What is EMF (electromotive force)?
