Physics 11–12 · Year 12
The photoelectric effect: stopping-voltage simulation and a bench estimate of Planck's constant from LEDs
Module 7: The Nature of Light (Light: Quantum Model)
Teacher-led practical
A teacher carries out this practical while the class watches. Its materials, steps, variables, misconceptions and sources are not published on the open web, and neither is any result, control or note that states a number or an amount: tutors and administrators read them on the learning platform, with the safety card first. The idea, the hazards and the curriculum references are below.
Open the procedure on the learning platform (tutor or administrator sign-in)
School laboratory, not for home
In a school laboratory, with a teacher supervising, under the school's risk assessment. Not for home.
This Lab page has no on-screen model. Where a step or a material names a model, simulation or tool, it was planned when the practical was written and is not on this site; an external simulation a step names (for example PhET) is not part of this site.
The idea
Light delivers energy in packets proportional to frequency, so electrons leave a metal only above a threshold frequency and their maximum energy grows with frequency, not intensity.
Safety card
Setting: In a school laboratory, with a teacher supervising, under the school's risk assessment. Not for home.
Hazards
- short-wave (UV-C) lamp: brief direct exposure can burn the cornea (photokeratitis) and redden the skin
- bright LEDs viewed closely
Controls
- the UV-C step is a teacher-only demonstration in a school laboratory and is never done at home: lamp shielded and pointed away from everyone, UV-blocking eye protection, exposures kept short
- view LEDs at low current only
Note
Record the activity in RiskAssess (https://www.riskassess.com.au/) and follow the Science ASSIST risk management information sheet (https://asta.edu.au/resource/ais-risk-management-and-risk-assessment/).
What you should see
It states a number or an amount, which may be part of the method, so it is shown with the method to tutors and administrators on the learning platform.
Curriculum references
The NSW syllabus outcomes and Australian Curriculum v9 codes this practical supports. They are references, not a verified or complete curriculum alignment.
- Physics Stage 6 Syllabus (2017), current: Year 11 until the end of 2026, Year 12 until Term 3 2027PH12-14PH11/12-4
- Physics 11-12 Syllabus (2025), not yet taught: Year 11 from Term 1 2027, Year 12 from Term 4 2027, first HSC examination 2028PY-12-03PY-12WS-05
- Australian Curriculum v9No Australian Curriculum v9 code is listed.