Light and Quantized Energy

Front

Electromagnetic radiation Noun

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[eh-lek-tro-mag-net-ik ray-dee-ay-shun]

Back

Electromagnetic radiation

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A form of energy that exhibits wavelike behavior as it travels through space, consisting of oscillating electric and magnetic fields.

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Example: This diagram shows the electromagnetic spectrum, arranging different types of radiation like radio waves and X-rays by their wavelength, with visible light as one part.

Front

Wavelength Noun

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[wayv-length]

Back

Wavelength

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The shortest distance between equivalent points on a continuous wave, such as from one crest to the next crest.

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Example: This diagram shows a wave, and the wavelength is the distance from one point on the wave, like a peak, to the next identical point.

Front

Frequency Noun

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[free-kwen-see]

Back

Frequency

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The number of waves that pass a given point per second, measuring how often a wave cycle repeats.

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Example: This diagram shows a wave with few cycles passing over time (t), which represents a low frequency. Light with low frequency has less energy.

Front

Hertz Noun

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[hurts]

Back

Hertz

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The SI unit of frequency, which is equivalent to one wave or cycle passing a point per second.

Front

Amplitude Noun

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[am-pli-tood]

Back

Amplitude

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A wave's height from the origin to a crest, or from the origin to a trough, indicating its intensity.

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Example: This diagram shows that the amplitude of a wave is its maximum height from the center line (equilibrium) to its highest point (crest).

Front

Electromagnetic spectrum Noun

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[eh-lek-tro-mag-net-ik spek-trum]

Back

Electromagnetic spectrum

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The entire range of electromagnetic radiation, distinguished by differences in frequency and wavelength from radio waves to gamma rays.

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Example: This diagram shows the electromagnetic spectrum, a range of all types of radiation, ordered by increasing frequency and decreasing wavelength, from radio waves to gamma rays.

Front

Quantum Noun

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[kwon-tum]

Back

Quantum

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The minimum amount of energy that can be gained or lost by an atom in a single interaction.

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Example: This diagram shows an atom where electrons exist only in specific shells, not in between. These fixed shells represent distinct, or 'quantized,' energy levels.

Front

Planck's constant Noun

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[planks kon-stunt]

Back

Planck's constant

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A fundamental physical constant used to calculate the energy of a quantum, with a value of 6.626 × 10⁻³⁴ J·s.

Front

Photoelectric effect Noun

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

Back

Photoelectric effect

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The emission of electrons from a metal's surface when light of a certain minimum frequency shines on it.

Front

Photoelectron Noun

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[foh-toh-ee-lek-tron]

Back

Photoelectron

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An electron that is emitted from a metal's surface as a direct result of the photoelectric effect.