Search results
Results from the WOW.Com Content Network
For comparison, a conventional incandescent light bulb of 60–100 watts emits around 15 lm/W, and standard fluorescent lights emit up to 100 lm/W. As of 2012, Philips had achieved the following efficacies for each color. [8] The efficiency values show the physics – light power out per electrical power in.
If one illuminates two parallel slits, the light from the two slits again interferes. Here the interference is a more pronounced pattern with a series of alternating light and dark bands. The width of the bands is a property of the frequency of the illuminating light. [20] (See the bottom photograph to the right.) Young's drawing of diffraction
A blazed diffraction grating reflecting only the green portion of the spectrum from a room's fluorescent lighting. For a diffraction grating, the relationship between the grating spacing (i.e., the distance between adjacent grating grooves or slits), the angle of the wave (light) incidence to the grating, and the diffracted wave from the grating is known as the grating equation.
The equation PV = nRT represents the ideal gas law, where P is the pressure of the gas, V is the volume, n is the number of moles, R is the universal gas constant, and T is the temperature. Gibbs's free energy formula
By using ∇ × (∇ × u) = ∇(∇ ⋅ u) − ∇ ⋅ ∇ u = ∇(∇ ⋅ u) − ∆u, the elastic wave equation can be rewritten into the more common form of the Navier–Cauchy equation. Note that in the elastic wave equation, both force and displacement are vector quantities. Thus, this equation is sometimes known as the vector wave equation.
The bulb's "turn on" voltage V b is higher than its "turn off" voltage V e. This property, called hysteresis, allows the bulb to function as an oscillator. Hysteresis is due to the bulb's negative resistance, the fall in voltage with increasing current after breakdown, [7] [14] which is a property of all gas-discharge lamps.
Historian Thomas Hughes (1977) describes the features of Edison's method. In summary, they are: Hughes says, "In formulating problem-solving ideas, he was inventing; in developing inventions, his approach was akin to engineering; and in looking after financing and manufacturing and other post-invention and development activities, he was innovating."
According to the "strong" form of Fermat's principle, the problem of finding the path of a light ray from point A in a medium of faster propagation, to point B in a medium of slower propagation , is analogous to the problem faced by a lifeguard in deciding where to enter the water in order to reach a drowning swimmer as soon as possible, given ...