The light produced by a red neon sign is due to the emission of light by excited neon atoms. Qualitatively describe the spectrum produced by passing light from a neon lamp through a prism.
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Chemistry 2e · 6.1 Electromagnetic Energy
Electromagnetic Energy: practice problems
8 problems from the book, with its answers. Check your working, or have any of them explained to you on the whiteboard.
Exercises 3
FM-95, an FM radio station, broadcasts at a frequency of 9.51 10⁷ s⁻¹ (95.1 MHz). What is the wavelength of these radio waves in meters?
Exercises 5
Light with a wavelength of 614.5 nm looks orange. What is the energy, in joules, per photon of this orange light? What is the energy in eV (1 eV = 1.602 10⁻¹⁹ J)?
Exercises 7
Exercises 9
Exercises 11
Exercises 13
Exercises 15
Key terms · 17
- amplitude
- extent of the displacement caused by a wave
- blackbody
- idealized perfect absorber of all incident electromagnetic radiation; such bodies emit electromagnetic radiation in characteristic continuous spectra called blackbody radiation
- continuous spectrum
- electromagnetic radiation given off in an unbroken series of wavelengths (e.g., white light from the sun)
- electromagnetic radiation
- energy transmitted by waves that have an electric-field component and a magnetic-field component
- electromagnetic spectrum
- range of energies that electromagnetic radiation can comprise, including radio, microwaves, infrared, visible, ultraviolet, X-rays, and gamma rays
- frequency (ν)
- number of wave cycles (peaks or troughs) that pass a specified point in space per unit time
- hertz (Hz)
- the unit of frequency, which is the number of cycles per second, s^−1
- intensity
- property of wave-propagated energy related to the amplitude of the wave, such as brightness of light or loudness of sound
- interference pattern
- pattern typically consisting of alternating bright and dark fringes; it results from constructive and destructive interference of waves
- line spectrum
- electromagnetic radiation emitted at discrete wavelengths by a specific atom (or atoms) in an excited state
- node
- any point of a standing wave with zero amplitude
- photon
- smallest possible packet of electromagnetic radiation, a particle of light
- quantization
- limitation of some property to specific discrete values, not continuous
- standing wave
- (also, stationary wave) localized wave phenomenon characterized by discrete wavelengths determined by the boundary conditions used to generate the waves; standing waves are inherently quantized
- wave
- oscillation of a property over time or space; can transport energy from one point to another
- wavelength (λ)
- distance between two consecutive peaks or troughs in a wave
- wave-particle duality
- observation that elementary particles can exhibit both wave-like and particle-like properties
Learn 6.1 on the whiteboard
The tutor teaches the whole section, drawing it out step by step and answering your questions as you go.