Question

The ratio of the energy of a photon of $2000\stackrel{o}{A}$ wavelength radiation to that of $4000\stackrel{o}{A}$ radiation is:

• A. $\frac{1}{4}$
• B. $4$
• C. $\frac{1}{2}$
• D. $2$

Answer 1

The correct option is D $2$

We know, energy $\left(E\right)=\frac{hc}{\lambda }$
Where, $h=\text{Planck's constant}$
$\lambda =\text{Wavelength}$
Let, ${\lambda }_1=2000\stackrel{o}{A}$
${\lambda }_2=4000\stackrel{o}{A}$
Let , $E_1=\text{energy of a photon of}2000\stackrel{o}{A}\text{wavelength radiation}$
$E_2=\text{energy of a photon of}4000\stackrel{o}{A}\text{wavelength radiation}$
So, $\frac{E_1}{E_2}=\frac{{\lambda }_2}{{\lambda }_1}=\frac{4000}{2000}=2$