Science · Grades 7–12
Waves and electric circuits · quick reference
Voltage is measured across a component; current is measured through a path. Never practise these concepts on household mains wiring.
Key terms at a glance
Electric current
The rate at which electric charge passes a point.
Potential difference
Energy transferred per unit charge between two points.
Resistance
The ratio of potential difference to current for the stated operating conditions.
Series circuit
A circuit arrangement with components connected along one current path.
Parallel circuit
A circuit arrangement with branches connected across the same two nodes.
Closed circuit
A complete conducting path that permits a steady current when driven by a source.
Open circuit
An interrupted path that prevents a steady current through that path.
Insulator
A material that strongly resists charge flow under ordinary conditions.
Frequency
The number of complete cycles per unit time.
Period
The time taken for one complete cycle.
Wavelength
The distance between successive points in the same phase on a wave.
Amplitude
The maximum displacement from equilibrium for an oscillation.
Reflection
The return of a wave from a boundary into the original medium.
Refraction
A change in wave direction associated with a change in propagation speed at a boundary.
Diffraction
The spreading or bending of waves around obstacles or through openings.
Transverse wave
A wave whose oscillations are perpendicular to its propagation direction.
Longitudinal wave
A wave whose oscillations are parallel to its propagation direction.
Electromagnetic wave
A propagating pattern of electric and magnetic fields that can travel through vacuum.
Sound wave
A mechanical disturbance that travels through a material medium.
Resonance
A strong response when a system is driven near one of its natural frequencies.
Further reading and review references
These are reference links, not copied exercises, institutional endorsement or proof of independent review.
Learning preview · teacher review required. Grade bands are approximate, not official curriculum alignment.