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Recap - Measure with a CD

Part of the Optics, Waves and Modern Physics section of Coddy's Physics journey. Lesson 33 of 53.

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Challenge

A CD's tracks are 1.6 μm apart, so it reflects light like a grating. A red laser pointer shines on it and makes a first-order spot on a wall 0.5 m away, 0.235 m to the side of the middle spot. First find the angle θ, then the laser's wavelength λ, in nm.

Try it yourself

All lessons in Optics, Waves and Modern Physics

1Reflection and Refraction

Reflection of LightThe Refractive IndexSnell's LawTotal Internal ReflectionDispersionApparent DepthRecap - Optical Fiber

4Mechanical Waves

What a Wave IsTwo Graphs of a WaveWhen Pulses MeetInterferenceStanding WavesHarmonicsRecap - Guitar String

7Photons

Light Comes in PhotonsThe Photoelectric EffectEinstein's EquationStopping VoltageCounting PhotonsRecap - Solar Cell

10Nuclear Energy

Mass DefectBinding Energy per NucleonFission and FusionRecap - Inside the Sun

2Plane Mirrors

The Image in a MirrorSeeing in a MirrorTwo MirrorsRecap - Periscope

5The Ripple Tank

Two SourcesNodal LinesHow the Pattern ChangesRecap - Two Speakers

8The Bohr Atom

The Bohr ModelEmission and AbsorptionSpectral LinesRecap - Hydrogen Lamp

3Thin Lenses

Lenses and Their RaysThe Lens EquationVirtual ImagesTwo LensesA Lens and a MirrorRecap - Build a Projector

6Light as a Wave

Light Through Two SlitsFringes on a ScreenDiffraction by One SlitThe Diffraction GratingRecap - Measure with a CD

9The Nucleus

Inside the NucleusRadioactive DecayHalf-LifeActivityRadioactive DatingRecap - Carbon Dating