Question

Calculate the ratio between the energy of two radiation one with a wavelength of 6000 $\stackrel{o}{A}$ and the other with 2000 $\stackrel{o}{A}$.

• A. $3:1$
• B. $1:3$
• C. $2:1$
• D. $1:2$

Answer 1

The correct option is B $1:3$

Given that:
${\lambda }_1=6000\stackrel{0}{A}$ and ${\lambda }_2=2000\stackrel{0}{A}$

$E_1=\frac{hc}{{\lambda }_1}$ and $E_2=\frac{hc}{{\lambda }_2}$
So,
$\frac{E_1}{E_2}=\frac{\frac{hc}{{\lambda }_1}}{\frac{hc}{{\lambda }_2}}=\frac{{\lambda }_2}{{\lambda }_1}=\frac{1}{3}$