Question

What is the change in energy of an atom if the wavelength of the photon absorbed by the atom is equal to 4.64 x 10-7 meters? (Planck’s constant is 6.626 x 10-34 joule seconds; the speed of light is 2.998 x 108 m/s)?
A.
1.428 x 10-41 joules second
B.
3.074 x 10-26 joules
C.
3.440 x 10-19 joules/second
D.
4.281 x 10-19 joules
E.
10.255 x 10-49 joule second

Answer 1

Answer:

D.  4.281 x 10⁻¹⁹ Joules.

Explanation:

• To get the change in energy, we can use the relation:

E = (hc)/λ

where,

E is the energy of the atom.

h is Planck’s constant =  6.626 x 10⁻³⁴ J.s.

c is the speed of light = 2.998 x 10⁸ m/s.

λ is the wavelength of photon = 4.64 x 10⁻⁷ m.

∴ E = (hc)/λ = (6.626 x 10⁻³⁴ J.s)(2.998 x 10⁸ m/s)/(4.64 x 10⁻⁷ m) = 4.281 x 10⁻¹⁹ J.