--%>
Assignment Help - homework help

Define Lumen or SI unit of luminous flux

Lumen: lm: The derived SI unit of luminous flux, stated as the luminous flux produced by a uniform point source of 1 cd releasing its luminous energy over a solid angle of 1 sr; it therefore has units of cd sr.

   Related Questions in Physics

  • Q : Define Siemens or SI unit of an

    Siemens: S (after E.W. von Siemens, 1816-1892): The derived SI unit of an electrical conductance equivalent to the conductance of an element which has a resistance of 1 O [ohm]; this has units of O-1.

    		•
  • Q : Define Atwood's machine Atwood's

    Atwood's machine: The weight-and-pulley system devised to compute the acceleration due to gravity at Earth's surface by computing the total acceleration of a set of weights of identified mass about a frictionless pulley.

    		•
  • Q : What is Permeability of free space or

    Permeability of free space: magnetic constant: mu_0: The ratio of the magnetic flux density in the substance to the external field strength for vacuum. It is equivalent to 4 pi x 10-7 H/m.

    		•
  • Q : Define Newton or SI unit of force

    Newton: N (after Sir I. Newton, 1642-1727): The derived SI unit of force, stated as the force needed to give a mass of 1 kg of an acceleration of 1 m/s2; it therefore has units of kg m/s2.

    		•
  • Q : Define Planck equation Planck equation:

    Planck equation: The quantum mechanical equation associating to the energy of a photon E to its frequency nu: E = h nu.

    		•
  • Q : Explain Millikan oil drop experiment

    Millikan oil drop experiment (R.A. Millikan): A famed experiment designed to compute the electronic charge. The drops of oil were carried past a consistent electric field among charged plates. Subsequent to charging the drop with x-ra

    		•
  • Q : Define Dirac constant Dirac constant :

    Dirac constant: Planck constant, modified form; hbar Sometimes more suitable form of the Planck constant, stated as: hbar = h/(2 pi)

    		•
  • Q : Explain Stefan-Boltzmann law

    Stefan-Boltzmann law (Stefan, L. Boltzmann): The radiated power P (that is the rate of emission of electromagnetic energy) of a hot body is proportional to the radiating surface area, A, and the 4th power of the thermodynamic temperature, T. The const

    		•
  • Q : Calculate time needed for thermocouple

    A thermocouple of K type is suddenly exposed to air with temperature of 1273K, Initial temperature was 293 K. Calculate the time needed for the thermocouple read the temperature with accuracy of better that 99%. Ignore radiation and conduction. The measuring element has a ball shape of diameter o

    		•
  • Q : Explain Keplers laws or Keplers

    Explain Keplers laws or Keplers first law, second law and third law? Kepler's laws (J. Kepler) Kepler's first

    		•