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  2. Pyrgeometer - Wikipedia

    en.wikipedia.org/wiki/Pyrgeometer

    A pyrgeometer is a device that measures near-surface infra-red (IR) radiation, approximately from 4.5 μm to 100 μm on the electromagnetic spectrum (thereby excluding solar radiation). It measures the resistance / voltage changes in a material that is sensitive to the net energy transfer by radiation that occurs between itself and its ...

  3. Thermodynamic activity - Wikipedia

    en.wikipedia.org/wiki/Thermodynamic_activity

    The relative activity of a species i, denoted a i, is defined [4] [5] as: = where μ i is the (molar) chemical potential of the species i under the conditions of interest, μ o i is the (molar) chemical potential of that species under some defined set of standard conditions, R is the gas constant, T is the thermodynamic temperature and e is the exponential constant.

  4. Pyranometer - Wikipedia

    en.wikipedia.org/wiki/Pyranometer

    A pyranometer (from Greek πῦρ (pyr) 'fire' and ἄνω (ano) 'above, sky') is a type of actinometer used for measuring solar irradiance on a planar surface and it is designed to measure the solar radiation flux density (W/m 2) from the hemisphere above within a wavelength range 0.3 μm to 3 μm.

  5. Glossary of physics - Wikipedia

    en.wikipedia.org/wiki/Glossary_of_physics

    By definition, it is the amount of energy gained by the charge of a single electron moved across an electric potential difference of one volt. electronegativity A chemical property that describes the tendency of an atom or a functional group to attract electrons (or electron density) towards itself. electronics

  6. AP Chemistry - Wikipedia

    en.wikipedia.org/wiki/AP_Chemistry

    The 2014 AP Chemistry exam was the first administration of a redesigned test as a result of a redesigning of the AP Chemistry course. The exam format is now different from the previous years, with 60 multiple choice questions (now with only four answer choices per question), 3 long free response questions, and 4 short free response questions.

  7. Physical chemistry - Wikipedia

    en.wikipedia.org/wiki/Physical_chemistry

    Physical chemistry is the study of macroscopic and microscopic phenomena in chemical systems in terms of the principles, practices, and concepts of physics such as motion, energy, force, time, thermodynamics, quantum chemistry, statistical mechanics, analytical dynamics and chemical equilibria.

  8. A flying phobia affects more than 25 million Americans. Here ...

    www.aol.com/plane-accidents-triggering-people...

    But diagnostically, there is a definition of aerophobia, and people with it have sets of symptoms. There are physical symptoms of that fear — fast heartbeat, sweating, trembling, dizziness ...

  9. Electroanalytical methods - Wikipedia

    en.wikipedia.org/wiki/Electroanalytical_methods

    Potentiometry passively measures the potential of a solution between two electrodes, affecting the solution very little in the process. One electrode is called the reference electrode and has a constant potential, while the other one is an indicator electrode whose potential changes with the sample's composition.