The Electromagnetic Spectrum: Sample Problems

Try each one on paper first. Only then reveal the solution — reading a worked answer you never attempted teaches you almost nothing.

1. 1. A photon has a wavelength of 500 nm. Find its frequency.

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2. 2. Find the energy of that 500 nm photon.

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3. 3. Which carries more energy per photon: a 700 nm red photon or a 400 nm violet photon?

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4. 4. A device emits radiation with a wavelength of 3.0 cm. Which region is it, and what is a likely use?

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5. 5. Rank these by increasing photon energy: a dental X-ray, a TV remote, and a black light.

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6. 6. Why is UV dangerous to skin while radio waves are not?

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7. 7. Light has a frequency of 6.0 × 10¹⁴ Hz. Find its wavelength (c = 3.00 × 10⁸ m/s) and name the region.

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8. 8. A radio station broadcasts at 1.0 × 10⁸ Hz. What is the wavelength?

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9. 9. An X-ray has a wavelength of 1.0 × 10⁻¹⁰ m. What is its frequency?

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10. 10. A scientist shines infrared light on a sample and a microwave on another. Describe how each interacts with the molecules.

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11. 11. Why can X-rays and gamma rays ionize atoms while visible light cannot?

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Al says…

Remember the order with 'Raging Martians Invaded Venus Using X-ray Guns': Radio, Microwave, Infrared, Visible, Ultraviolet, X-ray, Gamma. Then walk through your house: radio in the car, microwave in the kitchen, infrared in the TV remote, visible from the lamp, UV out the window.