# What is the frequency of a wave of red light in the air where its wavelength is 6.8×10−7m?

Jul 1, 2018

Approximately $4.41 \cdot {10}^{14}$ meters.

#### Explanation:

Frequency of a photon is given by the equation:

$f = \frac{c}{\lambda}$

where:

• $f$ is the frequency in hertz $\left(1 \setminus {\text{Hz"-=1 \ "s}}^{-} 1\right)$

• $c$ is the speed of light, which is approximately $3 \cdot {10}^{8} \setminus \text{m/s}$

• $\lambda$ is the wavelength in meters

So, we get:

$f = \left(3 \cdot {10}^{8} \textcolor{red}{\cancel{\textcolor{b l a c k}{\text{m""s"^-1)/(6.8*10^-7 color(red)cancelcolor(black)"m}}}}\right)$

$\approx 4.41 \cdot {10}^{14} \setminus \text{m}$