Question

If at temperature $T_1=1000K$, the wavelength is $1.4\times {10}^{-6}m$, then at what temperature the wavelength will be $2.8\times {10}^{-6}m$

• A. 2000 K
• B. 500 K
• C. 250 K
• D. None of these

Answer 1

The correct option is B 500 K

${\lambda }_m\propto \frac{1}{T}\Rightarrow \lambda m_1{T}_1=\lambda m_2{T}_2$
$\Rightarrow T_2=\frac{\lambda m_1{T}_1}{\lambda m_2}=\frac{1.4\times {10}^{-6}\times 1000}{2.8\times {10}^{-6}}=500K$