# 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.

Q1:

Atomic emission spectra of the hydrogen atom show a red line at a wavelength of 656 nm. Given that the speed of light is and Planck’s constant is , what is the energy possessed by one photon at this wavelength?

• A
• B
• C
• D

Q2:

The atomic emission spectrum of the hydrogen atom shows a violet line at a wavelength of 434.0 nm. Calculate the energy of one photon at this wavelength. Use a value of for the speed of light and for Planck’s constant.

• A
• B
• C
• D

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.

Calculate the energy per mole of emitted photons.

Q8:

How many infrared photons with a wavelength of m must be absorbed by 190 g of water to increase the temperature from 25.0 to ? The specific heat capacity of water is 4.184 J/g⋅K.

• A83.0 mmol
• B82.4 mmol
• C77.7 mmol
• D86.4 mmol
• E90.9 mmol

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

Q10:

Heated sodium ions emit photons with an energy of J.

Calculate the wavelength of the emitted photons.

Calculate the energy per mole of emitted photons.

Q11:

A laser emits photons with an energy of J.

Calculate the frequency of the emitted photons.

• A Hz
• B Hz
• C Hz
• D Hz
• E Hz

Calculate the energy per mole of emitted photons.

Q12:

The emission spectrum of mercury vapor contains a bright green line at 546.1 nm. How much energy must an electron in a mercury atom release to produce a photon at this wavelength?

• 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

Q14:

A medical radiographic device emits an X-ray photon with a wavelength of m. Calculate the energy of this photon.

Q15:

A neon sign emits photons with a wavelength of 640 nm. Calculate the energy of one emitted photon.

• A J
• B J
• C J
• D J
• E J