Waves & Terms
Define "wavelength" in the context of an electromagnetic wave.
What is the distance between two consecutive corresponding points on a wave (e.g., crest to crest)?
Name two regions of the electromagnetic spectrum (other than visible light).
Examples: radio, microwave, infrared, ultraviolet, X-ray, gamma ray.
What is a "photon"?
Photon: a particle (quantum) of electromagnetic radiation that carries a discrete amount of energy.
Name the experiment or effect that showed electrons can be ejected from a metal when light of high enough frequency shines on it.
The photoelectric effect.
How many millimeters are in 1 meter?
What is 1000 mm.
Describe "frequency" and how does it relate to how often a wave cycles?
What is the number of wave cycles that pass a point per unit time.
Which region of the electromagnetic spectrum has longer wavelengths than visible light: infrared or ultraviolet?
What is Infrared.
Define "quantum" in the context of light energy.
Quantum: the smallest discrete amount of energy that can be absorbed or emitted.
What observation from the atomic emission spectrum of hydrogen helped scientists understand quantized energy levels?
The hydrogen atomic emission spectrum shows discrete lines at specific wavelengths, indicating electrons occupy quantized energy levels.
Name 2 items that are considered Personal Protective Equipment (PPEs) in the laboratory.
goggles, gloves, apron
Describe "amplitude" for an electromagnetic wave and what physical property it usually correlates with in light.
What is the maximum displacement from equilibrium; for light it often correlates with intensity or brightness.
Give the usual units used when reporting wavelength and frequency.
Wavelength: meters (m), nanometers (nm);
Frequency: hertz (Hz) or s-1.
State Planck's constant (symbol only) and briefly say what it represents.
Planck's constant: symbol h; it sets the scale for the quantum of action relating energy and frequency.
Briefly explain how the photoelectric effect supports the particle nature of light.
The photoelectric effect shows electrons are emitted only when incident light reaches a threshold frequency regardless of intensity, indicating light transfers energy in packets (photons).
What type of microscope is used in a high school laboratory?
Compound light microscope
Define the term "electromagnetic radiation" in one clear sentence.
What are waves of oscillating electric and magnetic fields that travel through space and can carry energy?
If a radio wave has a very low frequency, what can you say about its wavelength compared to visible light?
If frequency is very low, the wavelength is very long compared to visible light.
Write the formula that relates the energy of a photon to its frequency using symbols (do not compute).
Formula: E = h where E is photon energy and is frequency.
Describe what is meant by "light's dual nature."
The photoelectric effect shows electrons are emitted only when incident light reaches a threshold frequency regardless of intensity, indicating light transfers energy in packets (photons).
Convert 67,000 meters into Kilometers.
67 km
State the relationship between wavelength and frequency for electromagnetic waves (how changing one affects the other).
Relationship: wavelength and frequency are inversely proportional; as wavelength increases, frequency decreases and vice versa (for a given wave speed).
A light wave has wavelength 600 nm. Is this in the visible spectrum, and if so, which approximate color would it appear to the human eye?
600 nm is within the visible spectrum and appears orange to the human eye.
If the frequency of light doubles, what happens to the energy of a single photon? Explain in one sentence.
If frequency doubles, the photon energy doubles.
Explain how Planck's idea of quantized energy helped resolve the ultraviolet catastrophe in blackbody radiation (one to two sentences).
Planck proposed that energy is emitted in discrete quanta (integer multiples of h), which prevents the predicted infinite ultraviolet energy and matches observed blackbody spectra.
Change the following standard number into scientific notation using 3 significant figures:
9173005
9.17 x 10 e6