Green light has a wavelength of 5.0×10^2 nm. what is the energy in joules of one photon of green light?

3 Responses to Green light has a wavelength of 5.0×10^2 nm. what is the energy in joules of one photon of green light?

1. imshall77 says:

   March 29, 2011 at 11:52 am

   Frequency = speed of light/wavelength
   F = 3×10^8/5×10^-7 = 6×10^14 Hz

   Energy = Planks Constant x frequency
   E= 6.63×10^-34 * 6×10^14 = 3.978×10^-19 which is roughly equal to 4×10^-19 J for the energy of 1 photon of green light.

   4×10^-19 x 6.02×10^23 (Avogadro’s Number) = 240800 J per mole of photons of green light. This is 240000 J per mole when rounded to 2 s.f. as given in the question.
2. According To Me... says:

   March 29, 2011 at 11:00 am

   To solve this, you would use the formulas c=(lambda)v and E=hv.

   First you would plug in 5.0 x 10^-7 m into the first equation and solve for v, the frequency.

   3.0×10^8 m/s = (5.0×10^-7 m)v

   Once you solved for v, you would plug that into the equation E=hv, and solve for E. (By the way, the units for v is per seconds, or s^-1.)

   E=(6.636×10^-34 J/s)(your answer for v s^-1)

   h is Planck’s constant.

   This would give you the answer for one photon, and multiplying that by 6.02×10^23 would give you the answer for one mole.

   Hope this helps!
3. David says:

   March 29, 2011 at 10:34 am

   E=h*nu
   c=nu*lambda

   where h is plancks constant(m2 kg/s2), nu is frequency(1/m), lambda is wavelength (m), and E (J). that’s for one photon, so then just multiply by avogadro’s #.