Question #9754c
1 Answer
Explanation:
The idea here is that the energy of the photon is proportional to its frequency as shown by the Planck - Einstein relation
#color(blue)(|bar(ul(color(white)(a/a)E = h * nu color(white)(a/a)|)))#
Here you have
Notice that the problem provides you with the period of the wave,
#color(purple)(|bar(ul(color(white)(a/a)color(black)(T = 1/nu)color(white)(a/a)|)))#
This means that the frequency of the wave will be
#nu = 1/T#
#nu = 1/(2 * 10^(-15)"s") = 5 * 10^(14)"s"^(-1)#
Plug this into the Planck - Einstein relation to get
#E = 6.626 * 10^(-34)"J" color(red)(cancel(color(black)("s"))) * 5 * 10^(16)color(red)(cancel(color(black)("s"^(-1))))#
#E = color(green)(|bar(ul(color(white)(a/a)color(black)(3.3 * 10^(-17)"J")color(white)(a/a)|)))#
I'll leave the answer rounded to two sig figs.