The Structure of the Atom
What are atoms?
What are their properties?
Why are they important in chemistry?
You can download the power points using the following link:
Light Calculations WS
1. A red traffic light has an average wavelength corresponding to 690 nm. Calculate the frequency of this radiation.
2. The radiation used in microwave ovens, has a frequency of 2.43 x 10^9 Hz. Determine the wavelength, in nanometers, that corresponds to this frequency.
3. On a nice day the sky appears to be a beautiful blue color. This blue color appears because of the way air molecules scatter sunlight. A frequency of 7.6 x 10^14 Hz corresponds to the blue light.
a. Calculate the wavelength in nanometers that corresponds to this frequency of blue light.
b. Determine the energy, in joules (J) or eV, of a single photon of this blue light.
4.
a. Red light has a wavelength of about 710 nm. Calculate the energy of this red light.
b. Violet light has a wavelength of about 410 nm. Calculate the energy of this light.
c. Compare the energy of red and violet light. Which is more energetic? Explain.
5. A high-powered laser is pulsed for 200 ns. The total amount of energy associated with this signal is 16, 600 J. how many photons are emitted during this pulse, if the wavelength of the signal is 349 nm?
6. Metals absorb radiation and emit electrons from their surface, this is known as the photoelectric effect. Potassium, K, metal requires radiation with a minimum frequency of
5.60 x 10^14 Hz to release an electron.
a. Calculate the minimum energy required to cause the photoelectric effect in potassium.
b. Determine the wavelength that corresponds to this required energy.
c. Refer to page 156 in your textbook and identify the region of the electromagnetic spectrum to which this radiation belongs.
7. An engineer designs a switch that works by the photoelectric effect. The switch requires light of sufficient energy to strike the metal surface to make it turn on. The metal selected for the device requires radiation of 6.8 x 10^-19 J/atom to release an electron. Determine whether
or not the switch will work if the light striking the metal has a wavelength of 550 nm.
