What is the frequency of blue light with a wavelength of 400 nm?
A. 1.33 × 10³Hz
B. 7.50 × 10¹²Hz
C. 1.33 × 10¹⁴Hz
D. 7.50 × 10¹⁴Hz

Answer :

Answer:

[tex] f_{blue}= \frac{3x10^8 m/s}{4x10^{-7} m}= 7.5 x10^{14} Hz[/tex]

So then our answer would be:

D. 7.50 × 10¹⁴Hz

Explanation:

For this case we know the frequency for the blue light, given by the problem:

[tex] \lambda_{blue}= 400 nm[/tex]

We can convert this into m like this:

[tex] \lambda_{blue}= 400 nm *\frac{10^{-9}m}{1nm}= 400x10^{-9}m = 4x10^{-7}m[/tex]

We know that the speed of light is a constant and is given by:

[tex] v_{light}= 3x10^{8} \frac{m}{s}[/tex]

And assuming that we have a fundamental wave, we need to satisfy the following basic relationship:

[tex] v = \lambda f[/tex]

And if we solve for the frequency from the last formula we got:

[tex] f = \frac{v}{\lambda}[/tex]

Now if we replace the values given we have:

[tex] f_{blue}= \frac{3x10^8 m/s}{4x10^{-7} m}= 7.5 x10^{14} Hz[/tex]

So then our answer would be:

D. 7.50 × 10¹⁴Hz