spectral radiance

(noun)

measures of the quantity of radiation that passes through or is emitted from a surface and falls within a given solid angle in a specified direction.

Related Terms

Examples of spectral radiance in the following topics:

  • Planck's Quantum Hypothesis and Black Body Radiation

    • where $B$ is the spectral radiance of the surface of the black body, $T$ is its absolute temperature, $\lambda$ is wavelength of the radiation, $k_B$ is the Boltzmann constant, $h$ is the Planck constant, and $c$ is the speed of light.
    • Note that the spectral radiance depends on two variables, wavelength and temperature.

  • Emission Spectrum of the Hydrogen Atom

    • The emission spectrum of atomic hydrogen is divided into a number of spectral series.
    • All observed spectral lines are due to electrons moving between energy levels in the atom.
    • The spectral series are important in astronomy for detecting the presence of hydrogen and calculating red shifts.
    • The spectral lines are grouped into series according to n′.
    • The fine structure also results in single spectral lines appearing as two or more closely grouped thinner lines due to relativistic corrections.

  • Dark-Field Microscopy

  • X-Rays

    • This process produces an emission spectrum of x-rays at a few discrete frequencies, sometimes referred to as the spectral lines.
    • The spectral lines generated depend on the target (anode) element used and therefore are called characteristic lines.

  • Power-Law Distribution of Particle Energies

    • If the range of the power-law distribution is sufficiently large (at least an order of magnitude) we can take $x_1\rightarrow 0$ and $x_2 \rightarrow \infty$ in (23) so that the integral is simply a constant and we find that the spectral distribution is also a power-law $\omega^{-s}$ with a power-law index of $s=(p-1)/2$.

  • Synchrotron Absorption

    • Notice that the spectral index does not depend on the power-law index of the particle distribution but rather results from the power-law relationship between particle energy and frequency.

  • RBC Anatomy

    • The RBCs' distinctive red color is due to the spectral properties of the binding of hemic iron ions in hemoglobin.

  • Description of the Hydrogen Atom

    • In 1914, Niels Bohr obtained the spectral frequencies of the hydrogen atom after making a number of simplifying assumptions.
    • From this, the hydrogen energy levels and thus the frequencies of the hydrogen spectral lines can be calculated.

  • Visible Light

    • Colors that can be produced by visible light of a narrow band of wavelengths (monochromaticlight) are called pure spectral colors.
    • Quantitatively, the regions of the visible spectrum encompassing each spectral color can be delineated roughly as:

  • Painting in the Early Byzantine Empire

    • Gold represents the radiance of Heaven.