Question

Variation of radiant energy emitted by sun, filament of tungsten lamp and welding arc as a function of its wavelength is shown in figure. Which of the following option is the correct match? (IIT JEE 2005)

• A. Sun - T₃, tungsten filament - T₁, welding are - T₂
• B. Sun - T₂, tungsten filament - T₁, welding are - T₃
• C. Sun - T₃, tungsten filament - T₂, welding are - T₁
• D. Sun - T₁, tungsten filament - T₂, welding are - T₃

Answer 1

The correct option is A

Sun - T₃, tungsten filament - T₁, welding are - T₂

According to Wein's displacement law $\lambda m\times T$ = Constant

Here $\lambda m<\lambda m2<\lambda m1$ $\Rightarrow T_3>T_2>T_1$

The temperature of Sun is higher than that of welding arc which in turn is greater than tungsten filament.
Therefore $T_3$ is the Sun's temperature, $T_2$ the welding arc's and $T_1$ the tungsten filament's.