Question

Solar radiation emitted by sun resembles to that emitted by a black body at a temperature of $6000\text{K}$. Maximum intensity is emitted at a wavelength of about $4800\AA$. If the sun is cooled down from $6000\text{K}$ to $3000\text{K}$, then the peak intensity would occur at a wavelength of

• A. $4800\AA$
• B. $9600\AA$
• C. $2400\AA$
• D. $19200\AA$

Answer 1

The correct option is B $9600\AA$

Here, $T_1=6000\text{K},{\lambda }_1=4800\AA$
$T_2=3000\text{K},{\lambda }_2=?$
According to Wein's law
$\frac{{\lambda }_2}{{\lambda }_1}=\frac{T_1}{T_2}$
$\Rightarrow {\lambda }_2=\frac{T_1}{T_2}\times {\lambda }_1=\frac{6000}{3000}\times 4800=9600\AA$