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(a.) Calculate the wavelength of light in vacuum that has a frequency of 9.2 101

ID: 1494739 • Letter: #

Question

(a.) Calculate the wavelength of light in vacuum that has a frequency of 9.2 1011 Hz.

(b.) What is its wavelength in ethyl alcohol? (The index of refraction of ethyl alcohol is 1.361.)

(c.) Calculate the energy of one photon of such light in vacuum. Express the answer in electron volts.
(d) What is the properties of and effect on the energy of the photon when it enters the ethyl alcohol? (Select all that apply.)

the energy is not proportional to the frequency

the energy goes up

the energy does not change

the energy goes down

the energy is inversely proportional to the frequency

the energy is proportional to the frequency

Explanation / Answer

(a)
v = f*
= v/f = (3.0*10^8)/(9.2*10^11)
= 3.26 * 10^-4 m

(b)
Wavelength in ethyl alcohol, e = /n
e = (3.26 * 10^-4)/1.361
e = 2.39 * 10^-4 m

(c)
E = h*c/
Where, h = 4.1356 * 10^-15 ev/s

E = (4.1356 * 10^-15 * 3.0 * 10^8)/(3.26 * 10^-4)
E = 3.81 * 10^-3 eV

(d)
E = h*c/
As we can see, Energy is inversely proprtional to wavelength,
In Ethyl alcohol, Wavelength reduces so ,
Energy goes up.

We also know, v = f* , = v/f
E = h*f i.e
Energy is proportional to the frequency