Question

The graph shown in the figure represents energy density $E_A$ versus $\lambda$ for three sources sun, welding arc, tungsten filament.

• A. $1$-Tungsten, $2$-Welding arc, $3$-Sun
• B. $1$-Sun, $2$-Tungsten, $3$-Welding arc
• C. $1$-Sun, $2$-Welding arc, $3$-Tungsten
• D. $1$-Welding arc, $2$-Sun, $3$-Tungsten

Answer 1

The correct option is A $1$-Tungsten, $2$-Welding arc, $3$-Sun

solution:

According to Wien's law the wavelength ${\lambda }_m$corresponding to which energy emitted per sec area by a perfectly back body is maximum, is inversely proportional to the absolute temperature (T) of the black body. Temperature of sun would be maximum of the given three.

As ${\lambda }_{m}T=constant$

So ${\lambda }_m$for the sun is minimum

hence, correct answer is (a).