Search results
Results From The WOW.Com Content Network
The SI unit of irradiance is watts per square metre (W/m 2 = Wm −2). The unit of insolation often used in the solar power industry is kilowatt hours per square metre (kWh/m 2). [12] The Langley is an alternative unit of insolation. One Langley is one thermochemical calorie per square centimetre or 41,840 J/m 2. [13]
The angular diameter of the Earth as seen from the Sun is approximately 1/11,700 radians (about 18 arcseconds), meaning the solid angle of the Earth as seen from the Sun is approximately 1/175,000,000 of a steradian. Thus the Sun emits about 2.2 billion times the amount of radiation that is caught by Earth, in other words about 3.846×10 26 watts.
If the extraterrestrial solar radiation is 1,367 watts per square meter (the value when the Earth–Sun distance is 1 astronomical unit), then the direct sunlight at Earth's surface when the Sun is at the zenith is about 1,050 W/m 2, but the total amount (direct and indirect from the atmosphere) hitting the ground is around 1,120 W/m 2. [6]
The SI unit of irradiance is the watt per square metre (symbol W⋅m −2 or W/m 2). The CGS unit erg per square centimetre per second (erg⋅cm −2 ⋅s −1 ) is often used in astronomy . Irradiance is often called intensity , but this term is avoided in radiometry where such usage leads to confusion with radiant intensity .
Currently, Meralco is the Philippines' largest distribution utility with a franchise area of 9,337 square kilometers covering Metro Manila, the entire provinces of Bulacan, Rizal and Cavite, parts of the provinces of Laguna, Quezon and Batangas, and 17 barangays in Pampanga. The franchise area is home to 23 million people, roughly a quarter of ...
Pd (Watts/meter 2) = E × H (Volts/meter × Amperes/meter)where Pd = the power density, E = the RMS electric field strength in volts per meter, H = the RMS magnetic field strength in amperes per meter. [6] The above equation yields units of W/m 2. In the USA the units of mW/cm 2, are more often used when making surveys.
Radiant intensity, a radiometric quantity measured in watts per steradian (W/sr) Luminous intensity, a photometric quantity measured in lumens per steradian (lm/sr), or candela (cd) Irradiance, a radiometric quantity, measured in watts per square meter (W/m 2) Intensity (physics), the name for irradiance used in other branches of physics (W/m 2)
Sunlight enters the instrument through a window and is directed onto a thermopile which converts heat to an electrical signal that can be recorded. The signal voltage is converted via a formula to measure watts per square metre.