A bright yellow light from the emission spectrum of sodium has a frequency of 5.0 x 10 14

cycles/second (Hz). What is the wavelength of this yellow light?

1 answer

To find the wavelength of light given its frequency, we can use the formula that relates the speed of light (c), frequency (f), and wavelength (λ):

\[ c = \lambda \cdot f \]

Where:

  • \( c \) is the speed of light, approximately \( 3.0 \times 10^8 \) meters per second (m/s),
  • \( f \) is the frequency in hertz (Hz),
  • \( \lambda \) is the wavelength in meters (m).

We can rearrange this formula to solve for wavelength \( \lambda \):

\[ \lambda = \frac{c}{f} \]

Given:

  • \( f = 5.0 \times 10^{14} \) Hz,
  • \( c = 3.0 \times 10^8 \) m/s.

Now we can plug in the values:

\[ \lambda = \frac{3.0 \times 10^8 , \text{m/s}}{5.0 \times 10^{14} , \text{Hz}} \]

Calculating this gives:

\[ \lambda = \frac{3.0}{5.0} \times \frac{10^8}{10^{14}} = 0.6 \times 10^{-6} \text{ m} \]

Thus, converting \( 0.6 \times 10^{-6} , \text{m} \) to nanometers (1 m = \( 10^9 \) nm):

\[ \lambda = 0.6 \times 10^{-6} \text{ m} \times 10^9 \text{ nm/m} = 600 \text{ nm} \]

Therefore, the wavelength of the yellow light is approximately 600 nm.