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    Waves

    Revision notes · Physics

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    Lesson step 1 of 4Reflection, Refraction & The EM Spectrum

    Reflection, Refraction & The EM Spectrum

    Reflection: angle of incidence = angle of reflection (both measured from the normal).

    Refraction: waves change direction when they enter a different medium because their speed changes. Light entering a denser medium slows down and bends towards the normal.

    The electromagnetic spectrum (longest to shortest wavelength):

    Radio → Microwave → Infrared → Visible → Ultraviolet → X-ray → Gamma

    All EM waves travel at the speed of light in a vacuum (3 × 108 m/s), are transverse, and transfer energy.

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    Key Terms

    Frequency
    Number of complete waves passing a point per second, measured in Hz.
    Refraction
    Change in direction of a wave when it enters a different medium due to a change in speed.