Practice Electromagnetic Spectrum in Physics

Use these practice problems to test your method after reviewing the concept explanation and worked examples.

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Quick Recap

The complete continuum of all electromagnetic waves, organized in order of increasing frequency (or decreasing wavelength).

A 'rainbow' that extends far beyond visible light in both directions.

Showing a random 20 of 50 problems.

Example 1

medium
A gamma ray has wavelength 3ร—10โˆ’123\times10^{-12} m. Find its frequency in vacuum.

Example 2

challenge
Sunlight peaks near 500500 nm (visible). A star peaks at 100100 nm. Which region is the star's peak, and is the star hotter or cooler than the Sun (peak wavelength shorter for hotter)?

Example 3

easy
Sort by increasing wavelength: gamma, visible light, microwave.

Example 4

easy
Are all electromagnetic waves the same kind of wave?

Example 5

medium
Which EM region is responsible for warming your skin in sunlight?

Example 6

medium
Red light is about 700700 nm, blue about 450450 nm. Which has higher frequency?

Example 7

challenge
Two EM waves differ in frequency by a factor of 1000. By what factor do their wavelengths differ?

Example 8

medium
An FM radio wave at 100100 MHz: find its wavelength in vacuum.

Example 9

easy
Which EM region lies just beyond the red end of visible light, at lower frequency?

Example 10

hard
The visible spectrum runs from about 400 nm to 700 nm. Find the corresponding frequency range.

Example 11

medium
Why are gamma rays more dangerous than radio waves at the same intensity?

Example 12

hard
Order by increasing photon energy: red light, blue light, microwave, X-ray.

Example 13

medium
A wave at ฮป=50โ€‰cm\lambda = 50\,\text{cm} is most likely in which region?

Example 14

easy
Within visible light, which color has the highest frequency: red or violet?

Example 15

challenge
A medical X-ray has ฮป=0.05โ€‰nm\lambda = 0.05\,\text{nm}. Find its photon energy in electronvolts. (Use hcโ‰ˆ1240โ€‰eV\cdotpnmhc \approx 1240\,\text{eVยทnm}.)

Example 16

easy
As frequency increases across the EM spectrum, what happens to wavelength?

Example 17

easy
Arrange the following EM waves from lowest to highest frequency: visible light, X-rays, radio waves, ultraviolet, infrared, gamma rays, microwaves.

Example 18

easy
Which has a longer wavelength: radio waves or X-rays?

Example 19

medium
A cell phone tower transmits at 2.0โ€‰GHz2.0\,\text{GHz}. Find the wavelength.

Example 20

hard
A photon has energy 4ร—10โˆ’19โ€‰J4\times10^{-19}\,\text{J}. Use h=6.63ร—10โˆ’34โ€‰J\cdotpsh = 6.63\times10^{-34}\,\text{Jยทs} to find its frequency and region.
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