Get insightful responses to your questions quickly and easily on IDNLearn.com. Get accurate and detailed answers to your questions from our knowledgeable and dedicated community members.

What is the wavelength of light that is emitted when an excited electron in the hydrogen atom falls from [tex]n=5[/tex] to [tex]n=1[/tex]?

A. [tex]9.12 \times 10^{-8} m[/tex]
B. [tex]9.50 \times 10^{-8} m[/tex]
C. [tex]1.05 \times 10^7 m[/tex]
D. [tex]2.09 \times 10^{-18} m[/tex]


Sagot :

To determine the wavelength of light emitted when an electron in a hydrogen atom transitions from the energy level [tex]\(n=5\)[/tex] to [tex]\(n=1\)[/tex], we can use the Rydberg formula for hydrogen:

[tex]\[ \frac{1}{\lambda} = R \left( \frac{1}{n_f^2} - \frac{1}{n_i^2} \right) \][/tex]

Where:
- [tex]\(\lambda\)[/tex] is the wavelength of the emitted light,
- [tex]\(R\)[/tex] is the Rydberg constant (approximately [tex]\(1.097373 \times 10^7 \, \text{m}^{-1}\)[/tex]),
- [tex]\(n_i\)[/tex] is the initial energy level (in this case, [tex]\(n_i = 5\)[/tex]),
- [tex]\(n_f\)[/tex] is the final energy level (in this case, [tex]\(n_f = 1\)[/tex]).

Let's plug in the given values:

[tex]\[ R \approx 1.097373 \times 10^7 \, \text{m}^{-1} \][/tex]
[tex]\[ n_i = 5 \][/tex]
[tex]\[ n_f = 1 \][/tex]

Using these values in the Rydberg formula, the equation becomes:

[tex]\[ \frac{1}{\lambda} = 1.097373 \times 10^7 \left( \frac{1}{1^2} - \frac{1}{5^2} \right) \][/tex]

First, calculate the terms inside the parentheses:

[tex]\[ \frac{1}{1^2} = 1 \][/tex]
[tex]\[ \frac{1}{5^2} = \frac{1}{25} = 0.04 \][/tex]

So,

[tex]\[ \frac{1}{\lambda} = 1.097373 \times 10^7 \left( 1 - 0.04 \right) = 1.097373 \times 10^7 \times 0.96 \][/tex]

Next, calculate the product:

[tex]\[ \frac{1}{\lambda} \approx 1.05347808 \times 10^7 \, \text{m}^{-1} \][/tex]

Taking the reciprocal to find [tex]\(\lambda\)[/tex]:

[tex]\[ \lambda \approx \frac{1}{1.05347808 \times 10^7} \approx 9.4923651 \times 10^{-8} \, \text{m} \][/tex]

Thus, the wavelength of light that is emitted is approximately [tex]\(9.492 \times 10^{-8} \, \text{m}\)[/tex].

Among the given options, the closest value to this result is:

[tex]\[ \boxed{9.50 \times 10^{-8} \, \text{m}} \][/tex]