Calculate the frequency of each of the following wave lengths of electromagnetic radiation.

Question

a) 632.8 nmnm (wavelength of red light from helium-neon laser)

b) 503 nmnm (wavelength of maximum solar radiation)

c) 337.1 nmnm (wavelength of nitrogen laser)

Answer 1

For all of these, we are given the wavelength and asked to find the frequency. The expression that we use to do this is c = λν where

c = speed of light = 3x10⁸ m/sec

λ = wavelength in meters

ν = frequency in sec^-1 (Hz)

So, we will convert nm to meters, and then solve for frequency

(a). 632.8 nm x 1 m / 1x10⁹ m = 632.8x10^-9 m

3x10⁸ m/sec = (632.8x10^-9 m) (ν)

ν = 3x10⁸ m/sec / 632.8x10^-9 m

ν = 4.74x10¹⁴ sec^-1 = 4.74x10¹⁴ Hz = frequency

(b). 503 nm = 503x10^-9 m

Solve the same way as in (a)

Answer should be 5.96x10¹⁴ Hz

(c). 337.1 nm = 337.1x10^-9 m

Solve the same was as in (a)

Answer should be 9.06x10¹⁴ Hz