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Candlepower (abbreviated as cp or CP) is a unit of measurement for luminous intensity. It expresses levels of light intensity relative to the light emitted by a candle of specific size and constituents. The historical candlepower is equal to 0.981 candelas. In modern usage, candlepower is sometimes used as a synonym for candla.
A bolometer can be used to measure power at microwave frequencies. In this application, a resistive element is exposed to microwave power. A dc bias current is applied to the resistor to raise its temperature via Joule heating, such that the resistance is matched to the waveguide characteristic impedance. After applying microwave power, the ...
Luminous intensity. In photometry, luminous intensity is a measure of the wavelength -weighted power emitted by a light source in a particular direction per unit solid angle, based on the luminosity function, a standardized model of the sensitivity of the human eye. The SI unit of luminous intensity is the candela (cd), an SI base unit.
The 26th General Conference on Weights and Measures (CGPM) redefined the candela in 2018. [10] [11] The new definition, which took effect on 20 May 2019, is: The candela [...] is defined by taking the fixed numerical value of the luminous efficacy of monochromatic radiation of frequency 540 × 10 12 Hz, [a] K cd, to be 683 when expressed in the unit lm W −1, which is equal to cd sr W −1 ...
Figure 1. Waveguide slotted line. Slotted lines are used for microwave measurements and consist of a movable probe inserted into a slot in a transmission line.They are used in conjunction with a microwave power source and usually, in keeping with their low-cost application, a low cost Schottky diode detector and VSWR meter rather than an expensive microwave power meter.
Luminance is a photometric measure of the luminous intensity per unit area of light travelling in a given direction. [1] It describes the amount of light that passes through, is emitted from, or is reflected from a particular area, and falls within a given solid angle. The procedure for conversion from spectral radiance to luminance is ...
The tellurometer emits a microwave-frequency radio wave. The remote station carries a transponder that reradiates the incoming wave in a similar wave of more complex modulation. The resulting phase shift is a measure of the two-way distance travelled. The results appear on a cathode ray tube with circular sweep.
Burn rate (chemistry) In chemistry, the burn rate (or burning rate) is a measure of the linear combustion rate of a compound or substance such as a candle or a solid propellant. It is measured in length over time, such as millimeters per second or inches per second. Among the variables affecting burn rate are pressure and temperature.