Question

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

• A. $4800$ $\mathring{A}$
• B. $9600$ $\mathring{A}$
• C. $2400$ $\mathring{A}$
• D. $19200$ $\mathring{A}$

Answer 1

The correct option is B $9600$ $\mathring{A}$

According to Wien's displacement law,

${\lambda }_{m}T$ $=b$ (constant)

where ${\lambda }_m$= wavelength of peakintensityin radiation.

So, ${\lambda }_1{T}_1={\lambda }_2{T}_2$

Since temperature is halved, wavelength will double.

So, new peak will occur at $2\times 4800$ $\mathring{A}$ = $9600$ $\mathring{A}$