Electromagnetic Waves - AP Physics 2

State the order of electromagnetic spectrum regions by increasing frequency.

Radio, Microwave, Infrared, Visible, UV, X-ray, Gamma. Listed from lowest to highest frequency across the spectrum.
In which region do electromagnetic waves have the greatest energy per photon?

Gamma rays. Highest frequency means highest energy per photon.
Which electromagnetic waves are used in sterilization of medical equipment?

Ultraviolet (UV) rays. UV radiation kills bacteria and viruses effectively.
What is the range of wavelengths for visible light?

Approximately 400 nm to 700 nm. This range covers the spectrum from violet to red light wavelengths.
What is the typical frequency range for infrared waves?

$10^{11} \text{ Hz}$ to $10^{14} \text{ Hz}$ . Infrared falls between microwaves and visible light frequencies.
Which electromagnetic waves have the longest wavelength?

Radio waves. Radio waves have the lowest frequencies and longest wavelengths.
Identify the electromagnetic wave with the highest frequency.

Gamma rays. Gamma rays have the shortest wavelengths and highest frequencies.
Identify the electromagnetic spectrum region with the shortest wavelength.

Gamma rays. Shortest wavelength corresponds to highest frequency and energy.
Name the electromagnetic wave used in night vision technology.

Infrared. Detects heat radiation emitted by objects in darkness.
Identify the electromagnetic spectrum region used for thermal imaging.

Infrared. Infrared radiation is emitted by warm objects for heat detection.
What is the wavelength of a 100 MHz radio wave?

3 m. Using $\lambda = c/f$ with $c = 3 \times 10^8$ m/s and $f = 100 \times 10^6$ Hz.
What is Planck's constant value?

$6.626 \times 10^{-34} \text{ J}\times\text{s}$ . This fundamental constant relates photon energy to frequency.
Which electromagnetic wave is used in radar technology?

Microwaves. Microwaves reflect off objects for distance and speed detection.
What is the typical wavelength range for microwaves?

1 mm to 1 m. Microwaves fall between radio waves and infrared radiation.
Find the frequency of light with a wavelength of 600 nm in a vacuum.

$5 \times 10^{14} \text{ Hz}$ . Using $f = c/\lambda$ with $c = 3 \times 10^8$ m/s and $\lambda = 600 \times 10^{-9}$ m.
What part of the electromagnetic spectrum is used in remote controls?

Infrared. Infrared LEDs transmit signals to electronic devices.
Find the wavelength of a gamma ray with frequency $3 \times 10^{19} \text{ Hz}$ .

$1 \times 10^{-11} \text{ m}$ . Using $\lambda = c/f$ with $c = 3 \times 10^8$ m/s and given frequency.
What is the wavelength of light with a frequency of $6 \times 10^{14} \text{ Hz}$ ?

500 nm. Using $\lambda = c/f$ with $c = 3 \times 10^8$ m/s and given frequency.
State the relationship between frequency and wavelength of electromagnetic waves.

$c = f \times \text{wavelength}$ , where $c$ is the speed of light. Shows how speed equals frequency times wavelength in electromagnetic waves.
What region of the electromagnetic spectrum is visible to the human eye?

Visible light. Human eyes detect wavelengths roughly from 400-700 nanometers.
What is the frequency of a photon with an energy of $4 \times 10^{-19} \text{ J}$ ?

$6.05 \times 10^{14} \text{ Hz}$ . Using $f = E/h$ with given energy and Planck's constant.
Which electromagnetic wave is primarily responsible for sunburn?

Ultraviolet (UV) rays. UV radiation damages skin cells causing sunburn and cancer.
What is the speed of electromagnetic waves in a vacuum?

$3 \times 10^8 \text{ m/s}$ . This is the universal constant for all electromagnetic waves in vacuum.
Find the frequency of ultraviolet light with wavelength 250 nm.

$1.2 \times 10^{15} \text{ Hz}$ . Using $f = c/\lambda$ with $c = 3 \times 10^8$ m/s and $\lambda = 250 \times 10^{-9}$ m.
State the formula for energy of a photon.

$E = h \times f$ , where $h$ is Planck's constant. This shows photon energy is proportional to frequency.
What is the primary use of X-rays in the medical field?

Imaging internal body structures. X-rays penetrate soft tissue but are absorbed by bones.
Which electromagnetic waves are commonly used in communication satellites?

Microwaves. Microwaves penetrate atmosphere for satellite-to-Earth communication.
Which electromagnetic wave is used in MRI technology?

Radio waves. MRI uses radiofrequency waves to excite hydrogen nuclei.
State the relationship between energy and frequency of electromagnetic waves.

Energy is directly proportional to frequency. Higher frequency photons carry more energy per quantum.
Find the energy of a photon with frequency $5 \times 10^{14} \text{ Hz}$ .

$3.313 \times 10^{-19} \text{ J}$ . Using $E = hf$ with $h = 6.626 \times 10^{-34}$ J·s and given frequency.
Identify the electromagnetic wave with the lowest energy.

Radio waves. Longest wavelength means lowest frequency and lowest energy.
Which electromagnetic waves are absorbed by ozone in the atmosphere?

Ultraviolet (UV) rays. Ozone layer absorbs harmful UV radiation protecting Earth's surface.
Which electromagnetic waves are used in television broadcasting?

Radio waves. Radio waves carry television signals through the atmosphere.
Identify the electromagnetic wave with wavelengths shorter than visible light.

Ultraviolet rays. UV wavelengths are shorter than violet light at 400 nm.
What is the unit of frequency for electromagnetic waves?

Hertz (Hz). Hertz measures cycles per second for wave frequency.
Which region of the electromagnetic spectrum is used in cellular communication?

Microwaves. Microwaves penetrate atmosphere well for long-distance communication.
What is the primary application of microwaves in the kitchen?

Heating food. Microwaves excite water molecules causing food to heat up.
What is the frequency range for X-rays?

Approximately $10^{16} \text{ Hz}$ to $10^{19} \text{ Hz}$ . X-rays fall between UV and gamma rays in frequency.
Name the electromagnetic wave primarily used for broadcasting.

Radio waves. Radio waves carry audio and video signals over long distances.

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