Question

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

Answer 1

Okay, I am having trouble getting the right answer. I am getting 1.81 x 10 ^ 16

Answer 2

find the energy of one photon:

\[E=h \frac{ c }{\lambda }\]

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

Answer 3

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

Answer 4

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

Answer 5

@Preetha Hello, can you help me figure out what I'm dong wrong here?

Answer 6

3.38 x 10 ^-19 J

should be negative

Answer 7

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

Answer 8

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

Answer 9

oh i see. got it!

Answer 10

good stuff

Answer 11

I got j and kJ mixed. Usually killo means 1000 o_O

Answer 12

kilo is 1000.. there are 1000J in 1kJ

Answer 13

Makes sense. Thanks! This cleared my problem.

Answer 14

awesome, no prob dude !