A spherical filament is approximated as an ideal emitter

PHYSICS · Single correct · CBSE · Physics · Thermal Properties of Matter · Thermal Properties of Matter

Problem

A spherical filament is approximated as an ideal emitter. It radiates a steady power of

1.2\times10^{4}\,\text{W}

, and its spectrum peaks at

\lambda_{\text{peak}} = 970\,\text{nm}

. Constants:

\sigma = 5.67\times10^{-8}\,\text{W}\,\text{m}^{-2}\,\text{K}^{-4}

b = 2.90\times10^{-3}\,\text{m}\,\text{K}

. Which of the following is closest to the filament’s radius? (a)

9.2\times10^{-3}\,\text{m}

(b)

1.6\times10^{-2}\,\text{m}

(c)

4.6\times10^{-3}\,\text{m}

(d)

2.3\times10^{-3}\,\text{m}