Simple a.c. circuits: JAMB Physics Past Questions and Answers

What the JAMB syllabus covers in Simple a.c. circuits

Our summary: Alternating voltage and current, and how resistors, inductors and capacitors behave in a.c. circuits.

• Explanation of a.c. current and voltage
• Peak and r.m.s. values
• A.c. source connected to a resistor
• A.c. source connected to a capacitor: capacitive reactance
• A.c. source connected to an inductor: inductive reactance
• R-L-C circuits
• Vector diagram, phase angle and power factor
• Resistance and impedance
• Effective voltage in an R-L-C circuit
• Resonance and resonance frequency ($F_0 = \frac{1}{2\pi\sqrt{LC}}$)

Objectives

• identify a.c. current and d.c. voltage;
• differentiate between the peak and r.m.s. values of a.c.;
• determine the phase difference between current and voltage;
• interpret R-L-C circuits;
• analyse vector diagrams;
• calculate the effective voltage, reactance and impedance;
• recognize the condition by which the circuit is at resonance;
• determine the resonant frequency of R-L-C arrangement;
• determine the instantaneous power, average power and the power factor in a.c. circuits.

Syllabus content © The Joint Admissions and Matriculation Board (UTME).