Light as a wave and as a particle
Grade 11 Science Worksheet
Circle the best answer, or write your answer on the line.
Light of 7.5 × 10¹⁴ Hz falls on cesium (work function 2.1 eV). With h = 4.135667696 × 10⁻¹⁵ eV·s, what is the electrons' greatest kinetic energy, to 0.01 eV, Ari?
Light of 15 × 10¹⁴ Hz falls on zinc (work function 4.3 eV). With h = 4.135667696 × 10⁻¹⁵ eV·s, what is the electrons' greatest kinetic energy, to 0.01 eV, Esme?
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Work functions of some metals (HyperPhysics, from the CRC Handbook)
Metal Work function (eV) cesium 2.1 sodium 2.28 potassium 2.3 calcium 2.9 zinc 4.3 copper 4.7 Using the table, which metal gives up electrons to the lowest-energy photons, Jun?
- Cesium
- Zinc
- Copper
Using the table, 2.48 eV green photons shine on each metal. How many metals give up electrons, Kira?
- 1
- 3
- 6
Using the table, why does visible light free no electrons from copper, Luz?
- Visible light is too bright
- Its photons carry less than 4.7 eV
- Copper reflects the light back
Ultraviolet light already frees electrons from zinc. It is made brighter. What changes, Noah?
- No electrons leave
- Each electron leaves with more energy
- More electrons leave each second
Dim ultraviolet light shines on zinc. When do the first electrons leave, Pia?
- Almost at once
- Not until the light is brighter
- After the metal warms up
In the photon diagram, the n = 3 to n = 2 photon carries 1.89 eV. About what wavelength is it, Ren?
- About 2343 nm, infrared
- About 122 nm, ultraviolet
- About 656 nm, red
In the photon diagram, what energy would a photon from a drop straight from n = 3 to n = 1 carry, Tala?
Use the picture in question 8.
- 12.09 eV
- 1.89 eV
- 15.11 eV
In the photon diagram, can hydrogen at n = 1 absorb a 5 eV photon, Zee?
Use the picture in question 8.
- Yes: any photon can be absorbed
- Yes: it moves halfway to n = 2
- No: 5 eV matches no gap