# Worksheet: Energy and Wavelength

In this worksheet, we will practice using the Planck constant and speed of light to convert between energies and wavelengths of electromagnetic waves.

**Q3: **

Heated thallium ions emit photons with an energy of J.

Calculate the wavelength of the emitted photons.

Calculate the energy per mole of emitted photons.

**Q4: **

Heated barium ions emit photons with an energy of 2.722 eV.

Calculate the wavelength of the emitted photons.

Calculate the energy per mole of emitted photons.

**Q5: **

In a flame test, bismuth atoms emit photons with an energy of 4.042 eV.

Calculate the wavelength of the emitted photons.

Calculate the energy per mole of the emitted photons.

**Q6: **

Mercury atoms in a high-pressure lamp emit photons with an energy of 6.705 eV.

Calculate the wavelength of the emitted photons.

Calculate the energy per mole of emitted photons.

**Q7: **

The atomic emission spectrum of nitrogen contains a strong line corresponding to photons with an energy of J.

Calculate the wavelength of the emitted photons. Give your answer to 1 decimal place.

Calculate the energy per mole of emitted photons.

**Q9: **

Chlorophyll a strongly absorbs light with a wavelength of 680 nm. What is the energy of a photon of this light?

- A J
- B J
- C J
- D J
- E J

**Q13: **

The eye of a reptile sends a visual signal to its brain when the visual receptors are struck by photons with a wavelength of 865 nm. The signal is sent only if the total energy of the photons is greater than J. Calculate the minimum number of photons that must strike the eye in order to trigger a signal.

- A
- B
- C
- D
- E