1) A gamma ray has a frequency of 3.5 x 10 19 Hz. Determine the wavelength of th

ID: 798539 • Letter: 1

Question

1) A gamma ray has a frequency of 3.5 x 1019 Hz. Determine the wavelength of this radiation in nm and the energy of a photon of this radiation.

2a) The work function for Al is 6.54 x 10-19 J. Compute the longest wavelength of light that can be used to eject an electron.

2b) Determine the kinetic energy of an electron ejected from aluminum by light with a frequency of 1.40 x 1015 Hz.

3) Compute the frequency of light (in Hz) emitted by a hydrogen atom when making a transition from the n = 5 to n = 2 state.

A) c = fxl

l = c/f

= 3 x 10^(8) / 3.5 x 10^(19)

0.85 x 10^(-11) mts

B) hc/l = E

l = (6.5 x 10 ^(-34) x 3 x 10^(8)) / (6.54 x 10^(-19))

= 3 x 10^(-7) mts

C)h x f = 6.5 x 10^(-34) x 1.4 x 10^(15)

= 9.1 x 10^(-19) J

KE = (9.1 - 6.54)x 10^(-19) J = 2.56 x 10^(-19) J

D)E = -13.6/n^2

Eemitted = -13.6(1/4-1/25)

-13.6 x (0.21)

2.856 ev

2.8 x 1.6 x 10^(-19) J

4.48 x 10^(-19) J

l = ((6.5 x 10^(-34)) x (3 x 10^(8)) / 4.48 x 10^(-19)

4.35 x 10^(-7) mts

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