16) How many photons are contained in a burst of yellow light (589 nm) from a sodium lamp that contains 609 kJ of energy?

A) 3.37 * 1019 photons

B) 3.06 * 1030 photons

C) 1.81 * 1024 photons

D) 4.03 * 1028 photons

E) 2.48 * 1025 photons

The correct answer to this question is this one:

find the energy of one photon:

E=h * c/λ

divide the energy given by the energy of one photon of that wavelength

What I've done so far is convert wave length to m and energy to j.

E photon = h * x / wave length

E = (6.626 x 10^-43) (3.00 x 10^8) / 587 ^ - 9 = 3.38 x 10 ^18 J

3.38 x 10 ^18 J x 1000 kj / 1 j = 3.37 x 10 ^ 16 Kj

609 kJ / 3.37 x 10 ^ 16 Kj = 1.81 x 10 ^ 16

E = (6.626 x 10^-34) (3.00 x 10^8) / 587 ^ - 9 = 3.38 x 10 ^19 J

3.38 x 10 ^19 J x 1000 kj / 1 j = 3.37 x 10 ^ - 16 Kj

609 kJ / 3.37 x 10 ^ 16 Kj = 1.81 x 10 ^ 18 but the answer is 1.81 * 10^24 photons

3.38 x 10 ^-19 J

should be negative

then 3.38 x 10 ^18 J x 1kJ/1000 J

you're converting from J to kJ ... just like meters to kilometres, you wouldn't multiply you would divide