Work function — Science definition
Minimum energy needed to eject an electron from a surface in the model.
Where it is taught
- Photons, Photoelectric Effect & Wave–Particle Models — Modern Physics, Physics & Environmental Science, Grade 12
In use
A photon must provide at least the work function φ, the energy needed for emission.
Photons, Photoelectric Effect & Wave–Particle Models
Questions using work function
Problem 1
Hints
Write the relationship first; substitute with consistent units.
Answer and explanation
3 eV
5−2=3.
Problem 2
Hints
Below threshold, increased intensity alone does not supply more energy to each photon.
Answer and explanation
No. Each photon is below threshold; do not report negative kinetic energy as an emitted-electron result.
Problem 3
Answer and explanation
Kmax=1.5 eV=2.403×10⁻¹⁹ J; stopping-potential magnitude=1.5 V. At fixed photon energy, increasing intensity changes available electron number rather than this maximum.
Kmax=1.5 eV=2.403×10⁻¹⁹ J; stopping-potential magnitude=1.5 V.
At fixed photon energy, increasing intensity changes available electron number rather than this maximum.
Response criteria
- Use the stated measurements or conditions, with correct units.
- Connect the result to the physical or environmental mechanism or evidence relationship.
- Identify the assumption, model limit or further evidence requested.