Simple A. C. Circuits

Contents & notes: what this topic covers

Under Simple A. C. Circuits, the JAMB Physics syllabus expects you to study:

• 36. Simple A. C. Circuits
• (i) explanation of a.c. current and voltage;
• (ii) peak and r.m.s. values;
• (iii) a.c. source connected to a resistor;
• (iv) a.c source connected to a capacitor- capacitive reactance;
• (v) a.c source connected to an inductor inductive reactance;
• (vi) R-L-C circuits;
• (vii) vector diagram, phase angle and power factor;
• (viii) resistance and impedance;
• (ix) effective voltage in an R-L-C circuits;
• (x) resonance and resonance frequency: F0 = 2 LC

Study notes & guidance

Study Simple A. C. Circuits using a recommended Physics textbook that follows the JAMB syllabus. Work through the contents listed above one by one, make brief notes in your own words, and then practise as many questions on this topic as you can — in Physics, understanding and steady practice matter far more than memorising. Use the objectives below as a checklist: if you can do each one confidently, you have mastered this topic.

Objectives — candidates should be able to

After studying Simple A. C. Circuits, you should be able to:

1. Identify a.c. current and d.c. voltage;
2. Differentiate between the peak and r.m.s. values of a.c.;
3. Determine the phase difference between current and voltage;
4. Interpret R-L-C circuits;
5. Analyse vector diagrams;
6. Calculate the effective voltage, reactance and impedance;
7. Recognize the condition by which the circuit is at resonance;
8. Determine the resonant frequency of R-L-C arrangement;
9. Determine the instantaneous power, average power and the power factor in a. c. circuits.

These objectives are from the official JAMB syllabus. Use them as a checklist — if you can do each one confidently, you have mastered this topic.

Source: official JAMB UTME Physics syllabus (IBASS, jamb.gov.ng). Reproduced for study use. Last checked: 17 Sept 2026. Always confirm the current syllabus on the official portal.