Topic 2 Self-assessment Exercise
1.
i. Give the equation that relates the speed of light (c) to the frequency of the light (ν).
ii. Give the units of each parameter in the equation.
iii. Rearrange the equation to produce an equation relating the frequency of light to the
wavelength.
iv. Use this equation to find the frequency of light having a wavelength 456 nm.
v. Rearrange the equation to produce an expression for the wavelength.
vi. What is the wavelength of light with a frequency of 2.45 x 109 Hz?
2. The blue colour of the sky results from the scattering of sunlight by air molecules. Blue
light has a frequency of about 7.5 x 1014 Hz.
i. Calculate the energy of a single photon associated with this frequency.
ii. Photochemical reactions are reactions which are initiated by light energy. Calculate
the energy of a mole of photons with this energy.
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1.
i. Give the equation that relates the speed of light (c) to the frequency of the light (ν).
ii. Give the units of each parameter in the equation.
iii. Rearrange the equation to produce an equation relating the frequency of light to the
wavelength.
iv. Use this equation to find the frequency of light having a wavelength 456 nm.
v. Rearrange the equation to produce an expression for the wavelength.
vi. What is the wavelength of light with a frequency of 2.45 x 109 Hz?
2. The blue colour of the sky results from the scattering of sunlight by air molecules. Blue
light has a frequency of about 7.5 x 1014 Hz.
i. Calculate the energy of a single photon associated with this frequency.
ii. Photochemical reactions are reactions which are initiated by light energy. Calculate
the energy of a mole of photons with this energy.
Page 1 of 1
