Technician T5C: Capacitance, inductance, impedance and power math
These are the 12 official questions in group T5C of the 2026–2030 Technician question pool, with the correct answer marked and a plain-English explanation of why it's right. The real exam asks one question from this group.
Learn T5C step by stepThe Technician course teaches this group in a short guided lesson, then drills you on the questions you miss. Start with the free lessons to see how it works.
- T5C01Question 1
What describes the ability to store energy in an electric field?
- AInductance
- BResistance
- CFrequency
- DCapacitance Correct
Why: Storing energy in an electric field is capacitance.
- T5C02Question 2
What is the unit of capacitance?
- AFarad Correct
- BOhm
- CVolt
- DHenry
Why: Capacitance is measured in farads.
- T5C03Question 3
What describes the ability to store energy in a magnetic field?
- AAdmittance
- BCapacitance
- CResistance
- DInductance Correct
Why: Storing energy in a magnetic field is inductance.
- T5C04Question 4
What is the unit of inductance?
- ACoulomb
- BFarad
- CHenry Correct
- DOhm
Why: Inductance is measured in henries.
- T5C05Question 5
What is the unit of impedance?
- AVolt
- BAmpere
- CCoulomb
- DOhm Correct
Why: Impedance, like resistance, is measured in ohms.
- T5C06Question 6
What is the abbreviation for kilohertz?
- AkHz Correct
- Bkhz
- CKHz
- DKHZ
Why: Kilohertz is written kHz.
- T5C07Question 7
What is the abbreviation for megahertz?
- AmHz
- BmHZ
- CMhz
- DMHz Correct
Why: Megahertz is written MHz.
- T5C08Question 8
What formula is used to calculate electrical power (P) in a DC circuit?
- AP = I x E Correct
- BP = E / I
- CP = I2 x E
- DP = I / E
Why: Power equals current times voltage: P = I × E.
- T5C09Question 9
How much power is delivered by a voltage of 13.8 volts DC and a current of 10 amperes?
- A138 watts Correct
- B0.7 watts
- C23.8 watts
- D3.8 watts
Why: 13.8 V × 10 A = 138 W.
- T5C10Question 10
How much power is delivered by a voltage of 12 volts DC and a current of 2.5 amperes?
- A4.8 watts
- B30 watts Correct
- C14.5 watts
- D0.208 watts
Why: 12 V × 2.5 A = 30 W.
- T5C11Question 11
How much current is required to deliver 120 watts at a voltage of 12 volts DC?
- A0.1 amperes
- B10 amperes Correct
- C12 amperes
- D132 amperes
Why: I = P ÷ E = 120 W ÷ 12 V = 10 A.
- T5C12Question 12
What is impedance?
- AThe opposition to AC current flow Correct
- BThe inverse of resistance
- CThe inverse of reactance
- DThe power handling capability of a component
Why: Impedance is the opposition to AC current flow.
Learn T5C step by stepThe Technician course teaches this group in a short guided lesson, then drills you on the questions you miss. Start with the free lessons to see how it works.