Question

The sodium emission spectrum

contains one visible, yellow line, with a λ = 5.90 x 10-7 m.
c = 3.00 x 108 m/s
h = 6.626 x 10-34 J.s
What is the frequency of this light?

Answer 1

To find the energy, you need to use the following equation:

E = hc / w

In this formula,

-----> E = energy (J)

-----> h = Planck's Constant (6.626 x 10⁻³⁴ J*s)

-----> c = speed of light (3.00 x 10⁸ m/s)

-----> w = wavelength (m)

Once you have converted nanometers to meters, you can plug the given values into the equation and solve.

410 nm 1 m

------------- x ---------------------- = 4.10 x 10⁻⁷ m

1 x 10⁹ nm

E = hc / w

E = (6.626 x 10⁻³⁴ J*s)(3.00 x 10⁸ m/s) / (4.10 x 10⁻⁷ m)

E = 4.85 x 10⁻¹⁹ J