Mechanical Waves and Sound

Front

Electromagnetic wave Noun

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[ee-lek-troh-mag-net-ik wayv]

Back

Electromagnetic wave

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A transverse wave composed of oscillating electric and magnetic fields that propagates through space, carrying electromagnetic radiant energy.

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Example: The Sun sends energy to Earth as electromagnetic waves (radiation), which can travel through the vacuum of space without needing a medium.

Front

Electric field Noun

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[ee-lek-trik feeld]

Back

Electric field

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A region around a charged particle or object within which a force would be exerted on other charged particles.

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Example: This diagram shows the electric field lines around a positive charge (lines point out) and a negative charge (lines point in), illustrating the field's direction.

Front

Magnetic field Noun

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[mag-net-ik feeld]

Back

Magnetic field

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A region around a magnetic material or a moving electric charge within which the force of magnetism acts.

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Example: This diagram shows the invisible magnetic field around a bar magnet, with lines flowing from the North pole (N) to the South pole (S).

Front

Wavelength Noun

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[wayv-length]

Back

Wavelength

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The spatial period of a periodic wave, representing the distance over which the wave's shape repeats itself.

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Example: This diagram shows a wave and labels its wavelength as the distance from one peak to the next, a key property of mechanical waves.

Front

Frequency Noun

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[free-kwen-see]

Back

Frequency

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The rate at which a vibration occurs, measured as the number of complete wave cycles passing a point per unit time.

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Example: This graph shows a wave with a low frequency, meaning few wave cycles pass by over a specific period of time (t).

Front

Intensity Noun

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[in-ten-si-tee]

Back

Intensity

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The power transferred per unit area, where power is the rate at which a wave's energy flows.

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Example: This chart shows that sound intensity is measured in decibels (dB), providing examples from a quiet whisper to a loud jet takeoff.

Front

Electromagnetic radiation Noun

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[ee-lek-troh-mag-net-ik ray-dee-ay-shun]

Back

Electromagnetic radiation

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The emission or propagation of energy in the form of electromagnetic waves or photons through space or a material medium.

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Example: This diagram shows the electromagnetic spectrum, arranging different types of radiation like radio waves and X-rays by their increasing wavelength and energy.

Front

Photon Noun

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[foh-ton]

Back

Photon

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A discrete quantum or particle of electromagnetic radiation, carrying energy proportional to its radiation frequency but having zero rest mass.

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Example: This diagram shows photons (particles of light) hitting a metal surface, which causes electrons to be knocked out and released from the metal.

Front

Photoelectric effect Noun

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[foh-toh-ee-lek-trik uh-fekt]

Back

Photoelectric effect

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The phenomenon where electrically charged particles are released from a material when it absorbs electromagnetic radiation, such as light.

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Example: When light strikes a metal surface with enough energy, it can knock electrons loose, causing them to be ejected from the material.

Front

Electromagnetic spectrum Noun

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[ee-lek-troh-mag-net-ik spek-trum]

Back

Electromagnetic spectrum

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The entire distribution of electromagnetic radiation according to frequency or wavelength, from radio waves to gamma rays.

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Example: The electromagnetic spectrum is a range of different types of radiation, from long-wavelength radio waves to short-wavelength gamma rays, including the visible light we see.