Chemistry (Electrons in Atoms)
posted by Katie on .
The wavelength of visible light varies from 0.40 μm to 0.70 μm as the color of the light changes from violet to red. Calculate the energy of a photon whose wavelength is 0.67 μm
HINT: From the wavelength and the speed of light, we can get the frequency. Then the energy is simply hf. Use Planck's constant h in the proper units.

E = hc/wavelength.
You don't need to go through the frequency if you use the above equation. Wavelength must be inserted in meters. 
are the units for energy J*s

yes, if c is in m/s, and h is in joulesseconds

Energy is in J.
E = hc/w. h has units J*s. c is m/s. w is in m so we have J*s*m/s/m. m and s cancel to leave E in J. 
the wavelength of the light 310nm. calculate the wave length in meters.