Chapter 7

List the colors present in white light.

What kinds of molecules are responsible for the green color in spring leaves and the red color in fall leaves?

What is the relationship between the wavelength of light and its color (its energy)?

What is the function of sunscreen and of UV protection on sunglasses?

What prevents large amounts of high-energy UV and X-ray light from reaching the Earth’s surface where it can adversely affect humans?

What does the MHz dial on a radio signify?

What are phosphorescence and fluorescence? How do they differ?

Describe the difference between laser light and ordinary light.

Classify each of the following lasers as to type (solidstate, gas, dye, or semiconductor) and list its wavelength (include the region of the spectrum to which each wavelength corresponds): a. Nd:YAG b. helium–neon c. argon ion d. carbon dioxide

Describe the light-related discoveries of each of the following scientists and state their significance: a. Newton b. Roentgen c. Hertz d. Bloch and Purcell

The Sun is \(1.5 \times 10^{8} \mathrm{~km}\) from the Earth. How long does it take light to travel from the Sun to the Earth?

The speed of sound is \(330 \mathrm{~m} / \mathrm{s}\). If fireworks are \(1 \mathrm{~km}\) away, what is the length of the time delay between seeing the fireworks explode and hearing the sound?

Arrange the following three wavelengths of light in order of increasing energy per photon. a. \(300 \mathrm{~nm}\left(\mathrm{n}=\right.\) nano \(\left.=10^{-9}\right)\) b. \(100 \mathrm{~cm}\) c. \(10 \mathrm{~nm}\)

Which of the following types of light would be most likely to damage biological molecules? Why? a. infrared light b. visible light c. ultraviolet light

List two types of electromagnetic radiation that have wavelengths that are shorter than visible light.

List two types of electromagnetic radiation that have frequencies that are lower than ultraviolet light.

Calculate the wavelength of the radio waves used to produce the FM radio signal found at \(93.6\) megahertz (MHz) on the radio dial.

Calculate the wavelength of the radio waves used to produce the AM radio signal found at 1140 kilohertz \((\mathrm{kHz})\) on the radio dial.

If an FM radio wave signal has a wavelength of 3.55 m, what is its frequency?

Make a sketch representing the wave nature of light and label the wavelength. Suppose the sketch you just made corresponds to visible light. How would UV light be different? How would infrared light be different?

Of the following types of electromagnetic radiation— microwave, infrared, ultraviolet, and X-ray—which is most energetic and which is least energetic?

Of the following types of electromagnetic radiation— radio waves, microwaves, gamma rays, and visible— which one has the longest wavelength? Which one has the highest frequency?

Describe how white light interacts with a colored substance to make it look colored.