Question

Which of the following are in the ascending order of wavelength?

• A. $H_{\alpha },H_{\beta },H_{\gamma },...$ lines in the Balmer series of hydrogen atom
• B. Lyman limit, Balmer limit, and Paschen limit in the hydrogen spectrum
• C. Violet, blue, yellow and red colors in solar spectrum
• D. None of the above

Answer 1

Answer: (B), (C)

Violet, blue, yellow and red colors in solar spectrum
Lyman limit, Balmer limit, and Paschen limit in the hydrogen spectrum

$E=\frac{hc}{\lambda }$
As $E$ increases, wavelength decreases.
So, $H_{\alpha },H_{\beta }$ are in decreasing order.
Series Limit:
$\frac{1}{\lambda }=R\left(\frac{1}{n^2}\right)$
For Lymen series, $n=1$
For Balmer series, $n=2$
For Paschen series, $n=3$
Hence, wavelengths increases, as $n$ increases.
VIBGYOR spectrum shown in figure.