Question

Light with a wavelength of 5.0 . 10-7 m strikes a surface that requires 2.0 ev to eject an electron. Calculate the frequency of the glven wave.
1.5 x 102
6.0 x 1014
17 x 10-15
6.0 x 10-16​

Answer 1

Answer:

$6.0\cdot 10^{14} Hz$

Explanation:

The frequency and the wavelength of an electromagnetic wave are related by the wave equation:

$c=f \lambda$

where

$c=3.0\cdot 10^8 m/s$ is the speed of light

f is the frequency

$\lambda$ is the wavelength

For the light wave in this problem,

$\lambda = 5.0\cdot 10^{-7} m$ is the wavelength

So, solving the equation for f, we find its frequency:

$f=\frac{c}{\lambda}=\frac{3.0\cdot 10^8}{5.0\cdot 10^{-7}}=6.0\cdot 10^{14} Hz$