Help with this multiple choice question? (1 Viewer)

[meet86]

A 2W laser light emits light of wavelength 600nm, the number of photons emitted from the laser per minute will be closest to:

A) 6X10^12
B) 6X10^18
C) 6X10^22
D) 6X10^24

 

[Deliriously]

Is the question photons per second?
In that case, I got B

Energy of 1 photon:
E = hf
E = hc/λ
= 3.313x10^-19

1W is the energy consumption of 1J per second.

hence 2W = 2J/s

For number of photons transferred in 2J per second,
Number of emitted photons = 2/3.313x10^-19 = 6x10^18 photons

 

[tutorhunt]

Umm, ok:
I couldn't seem to find the answer, but I think B.
Reasoning:
E=hc/wavelength
= 3.313x10^-19
Watts= Joules/Seconds
2 watts = 2 joules/persecond
2 joules/energy per photon=
6.389776358 x 10^18
Since it says per minute, i guess multiply this value by 60?
Which results in 3.83387 x 10^20.

Bumping this thread, maybe some physics pros can come in and work it out. haha

 

[tutorhunt]

Is the question photons per second?
In that case, I got B

Energy of 1 photon:
E = hf
E = hc/λ
= 3.313x10^-19

1W is the energy consumption of 1J per second.

hence 2W = 2J/s

For number of photons transferred in 2J per second,
Number of emitted photons = 2/3.313x10^-19 = 6x10^18 photons

Got there before me, i agree