Question

When an electron transitions from $n=2$ to $n=5$, will it be visible to the naked eye?

• A. Yes, the emission occurs at $434nm$ which is the blue range of light
• B. Yes, the emission occurs at $434nm$ which is the red range of light
• C. No, the absorption occurs at the infrared red region of the electromagnetic spectrum
• D. No, the absorption occurs in the blue range of light but our eyes are unable to detect absorption

Answer 1

The correct option is A Yes, the emission occurs at $434nm$ which is the blue range of light

Transition from $n=2$ to $n=5$ lies in Balmer series range, whose wavelength can be calculated as:

$\frac{1}{\lambda }=\stackrel{-}{V}=R(\frac{1}{2^2}-\frac{1}{5^2})=1.09\times {10}^7(\frac{1}{2^2}-\frac{1}{5^2})$

$\Rightarrow \lambda =436nm$ which is in the blue light wavelength range.

Thus, it lies in a visible region.