Question

Question #89e4c

Answer 1

`4.3 * 10^(-21` `"J"`

Explanation:

The energy of a photon can be expressed in terms of its wavelength by using a form of the Planck - Einstein relation.

`E =h * c/(lamda)`

Here

• `E` is the energy of the photon
• `h` is Planck's constant, equal to `6.626 * 10^(-34)"J s"`
• `c` is the speed of light in a vacuum, usually given as `3 * 10^8"m s"^(-1)`
• `lamda` is the wavelength of the wave

So all you have to do here is to plug in the value you have for the wavelength of the photon and solve for `E`.

`E = 6.626 * 10^(-34)"J" color(red)(cancel(color(black)("s"))) * (3 * 10^8 color(red)(cancel(color(black)("m"))) color(red)(cancel(color(black)("s"^(-1)))))/(0.000046color(red)(cancel(color(black)("m"))))`

`E = color(darkgreen)(ul(color(black)(4.3 * 10^(-21)color(white)(.)"J")))`

The answer is rounded to two sig figs, the number of sig figs you have for the wavelength of the photon.