Chem help???

Question

In addition to continuous radiation, fluorescent lamps emit sharp lines in the visible region from a mercury discharge within the tube. Much of this light has a wavelength of 436 nm. What is the energy (in J) of one photon of this light?

Answer 1

Please remember the formula between the energy and frequency or wavelength:
E = hν = hc/λ
where E the energy in J, h the Plank constant 6.626x10^-34 J•s, ν the frequency in 1/s or Hz, c the speed of light 2.998x10^8 m/s, and λ the wavelength in m.
Please do the math. The homework is for you to practice, and that is the only way to learn. Thank you.