# What is an example of a Planck's constant practice problem?

May 23, 2015

Planck's constant, "h", can be used to find the energy of a photon of electromagnetic radiation. The equation is $E = h \nu$, where $E$ is energy in Joules (J), $h$ is Planck's constant, $6.626 \times 10 \left(- 34\right) J \cdot s$, and $\nu$ is the frequency. The unit for frequency is Hertz (Hz), and $\text{1 Hz="1/s}$ .

Practice Problem

The energy of a photon of red light is $2.84 \times {10}^{- 19} \text{J}$. What is it's frequency?

Solve the equation $E = h \nu$ for $\nu$.

$\nu = \frac{E}{h}$ =

(2.84xx10^(-19) cancel"J")/(6.626xx10(-34) cancel"J*s")=(4.29xx10^(14))/("s")=4.29xx10^(14)"Hz"