Question

Calculate (i) wave number (ii) frequency of yellow radiation having wavelength of $5800 \AA$.

Answer 1

Given,  

Yellow wavelength having radiation of 5800 λ.

We know that, Frequency  $\quad =\quad \sfrac { c }{ \lambda };$

Where, $c\quad =\quad 3\quad \times \quad { 10 }^{ 8 };$

If we apply the values in the formula then,

Frequency  $\quad=\quad 3\quad \times \quad \frac { { 10 }^{ 8 } }{ 5800 }$

Frequency  $\quad=\quad 0.51\quad \times \quad { 10 }^{ 5 }$

To find wave number, $Wave\quad number\quad =\quad \frac { Frequency }{ c }$

$=\quad \frac { 0.51\quad \times \quad { 10 }^{ 5 } }{ 3\quad \times \quad { 10 }^{ 8 } } \quad =\quad 0.17\quad \times \quad { 10 }^{ -3 }$