Question

According to Wein's law

• A. ${\lambda }_{m}T=constant$
• B. $\frac{{\lambda }_m}{T}=constant$
• C. $\frac{T}{{\lambda }_m}=constant$
• D. ${\lambda }_m+T=constant$

Answer 1

The correct option is A ${\lambda }_{m}T=constant$

According to Wein’s law $\lambda \times T_m=C$, on heating up to ordinary temperatures, only long-wavelength (red) radiation is emitted. As the temperature rises, shorter wavelengths are also emitted in more and more quantity. Hence the colour of radiation emitted by the hot wire shifts from red to yellow, then to blue and finally to white.