Question

A black body at $1227^{\circ} C$ emits radiations with maximum intensity at a wavelength of $5000\,?$ . If the temperature of the body is increased by $1000^{\circ} C$ , the maximum intensity will be observed at

• A. $4000\,?$
• B. $5000\,?$
• C. $6000\,?$
• D. $3000\,?$

Answer 1

Answer: (D)

$3000\,?$

Answer 2

According to Wiens law $\lambda_{m} T=$ constant (say $b$) where $\lambda_{m}$ is wavelength corresponding to maximum intensity of radiation and $T$ is temperature of the body in Kelvin. $\therefore \frac{\lambda_{m}}{\lambda_{m}}=\frac{T}{T}$ Given, $T=1227+273=1500\, K$ $T=1227+1000+273=2500\,K$ ${{\lambda }_{m}}=5000\,?$ Hence, $\lambda_{m}=\frac{1500}{2500}\times 5000=3000\,?$