What Range of Frequencies Corresponds to 400-700nm Wavelengths?

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SUMMARY

The range of frequencies corresponding to wavelengths of 400 to 700nm can be calculated using the formula f = v/λ, where v is the speed of light (3.00 x 108 m/s). For 400nm, the frequency is approximately 7.5 x 1014 Hz, or 750 THz, while for 700nm, the frequency is about 4.3 x 1014 Hz. The conversion from nanometers to meters is crucial, as 400nm equals 4 x 10-7 m. Understanding these calculations is essential for grasping the relationship between light wavelengths and their corresponding frequencies.

PREREQUISITES
  • Understanding of the speed of light (3.00 x 108 m/s)
  • Familiarity with the formula f = v/λ
  • Knowledge of unit conversions, particularly from nanometers to meters
  • Basic grasp of electromagnetic spectrum concepts
NEXT STEPS
  • Study the electromagnetic spectrum and its properties
  • Learn about unit conversions, specifically between nanometers and meters
  • Explore the implications of frequency in various applications, such as optics and telecommunications
  • Investigate the relationship between wavelength, frequency, and energy in photons
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Students in physics or engineering, educators teaching optics, and anyone interested in the properties of light and its applications in technology.

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Homework Statement



The human eye is sensitive to light of wavelengths from about 400 to 700nm. What range of frequencies does this range correspond to? Take the speed of light to be 3.00 x 10^8 m/s.

Homework Equations



f=v/lambda

The Attempt at a Solution



3.00 x 10^8 / 400,000m = 750 HZ

I didn't bother to find the frequency for 700nm because i know 750hz is wrong... the answer for frequency of 400nm is supposed to be 4.3x1014, but i have no idea why.
thanks for the help!
 
Physics news on Phys.org
400nm is not 40,000m.
Nanometers are small. To remember the powers of 10 remember the rhyme:

"mili-micro-nano-pico"
Each is a factor of 1/1000 so 400nm = 400/(1000,000,000) meters or 4x10^ -7 m.

now v/lambda = 3/4 10^8/10^-7 = .75 x 10^(8+7) = .75 x 10^15 = 7.5 x 10^14.
Or 750,000,000,000,000 equals (let's see kilo-mega-giga-tera) 750TeraHz.
 

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