Calculate the energy of a photon of electromagnetic radiation at each of the wavelengths indicated in Problem 39.

Explanation:

The wavelengths are:

a. 632.8 nm (wavelength of red light from helium–neon laser)

b. 503 nm (wavelength of maximum solar radiation)

c. 0.052 nm (a wavelength contained in medical X-rays)

Energy of photon of electromagnetic waves is expressed as:

E = hf

h is the Planck constant

f is the frequency of radiation

since f = c/w

E = hc/w

c is the velocity of light = 3×10^8m/s

w is the wavelength

h = 6.63 × 10^-34J/Hz

If w = 632.8 nm

w = 632.8 × 10^-9m

E = (6.63 × 10^-34)(3×10^8)/6.328 × 10^-7m

E = 3.143×10^{-34+8+7}

E = 3.143×10^-19Joules

If w = 503 nm

w = 503×10^-9m

E = (6.63 × 10^-34)(3×10^8)/5.03× 10^-7m

E = 3.954×10^{-34+8+7}

E = 3.954×10^-19Joules

If w = 0.052 nm

w = 5.2×10^-11m

E = (6.63 × 10^-34)(3×10^8)/5.2× 10^-11m

E = 3.825×10^{-34+8+11}

E = 3.825×10^-15Joules

this could be newton#'s law of cooling. the cooling curve is exponential

the old price per ounce is c/4.

the new price per ounce is c/3.6.

the ratio of the old price to the new one is

(c/4)/(c/3.6) = (c/c)×(3.6/4) = 0.9 . . = 9/10 . . "nine tenths" in either form