Please help I dont know how to solve

Question

Determine the energy, in J, of a photon with a wavelength of 309 nm. (h = 6.626 × 10⁻³⁴ J • s and c = 3.00 × 10⁸ m/s)

Answer 1

Use E = hc/λ

Before plugging in values, you want to change 309 nm to meters because c (speed of light) has units of meters per sec. We need out units to match. 309 nm = 309x10^-9 nm

E = (6.626x10^-34 Js)(3x10⁸ m/s) / 309x10^-9 m)

E = 6.43x10^-19 J