Question

c = 3.0 x 10⁸ m/s;        b = v/c;           g (gamma) = 1/sqrt[1 – b²];    u = (u’ + v) / (1 + u’v/c²);

E_ph = hf = hc/l;           P = esAT⁴;     s = 5.67 x 10^-8 Watts / m² / K⁴

1.Photon Energy. Calculate the energy of a visible-light photon having a wavelength of 450 nanometers. Express both in Joules and as electron-volts (eV).

2. Blackbody Radiation. The human body emits energy as infrared radiation. Take the absolute temperature T = 308 Kelvins; area = 1.5 m²; emissivity e = 0.2. Calculate the total amount of radiated power from this person.

Answer 1