Question #57b52
1 Answer
For part (a)
Explanation:
I'll show you how to calculate the energy of the photon given to you in part (a), and leave the other one to you as practice.
So, what do you know about the energy of a photon?
You know that its proportional to the frequency of the photon,
#E = nu *h "# , where
Since you are given the wavelength of the photon, you can calculate its frequency by using the inverse relationship that exists between wavelength,
#lamda * nu = c implies nu = c/(lamda)" "# , where
Use this relationship in the equation for the energy of the photon to get
#E = c/(lamda) * h#
Plug in your values to find
#E= (3.0 * 10^(8)color(red)(cancel(color(black)("m"))) color(red)(cancel(color(black)("s"^(-1)))) * 6.626 * 10^(-34)"J"color(red)(cancel(color(black)("s"))))/(5.0 * 10^4 * 10^(-9)color(red)(cancel(color(black)("m"))))#
#E = 3.976 * 10^(-21)"J"#
Round this off to two sig figs, the number of sig figs you have for the wavelength of the photon, to get
#E = color(green)(4.0 * 10^(-21)"J")#