Question

The wavelength of the first line of Balmer series is 6253 Å. What is the wavelength of 3rd line of Balmer series?

• A. 5731 Å
• B. 7132 Å
• C. 4136 Å
• D. 4372 Å

Answer 1

Answer: (C)

4136 Å

Answer 2

$\frac{1}{\lambda_{1}}$= Rz² $\left( \frac{1}{4} - \frac{1}{9} \right)$

$\frac{1}{\lambda_{2}}$=Rz² $\left( \frac{1}{4} - \frac{1}{25} \right)$

̃$\frac{\lambda_{2}}{\lambda_{1}}$= $\frac{5/36}{21/100}$=$\frac{5 \times 100}{21 \times 36}$

l₂ = $\frac{500 \times 6253}{21 \times 36}$= 4136 Å