What is the frequency of a sound wave with a period of 0.02 seconds? A. 20 Hz B. 50 Hz C. 100 Hz D. 200 Hz 相关知识点: 试题来源: 解析 B。频率等于周期的倒数,周期为 0.02 秒,频率 = 1/0.02 = 50Hz,所以选择 B 选项。反馈 收藏 ...
The article reports on plans by media research organization Mediamark Research (MRI) to use radio frequency identification (RFID) in order to passively measure magazine readership. It describes lab tests using RFID tags to signal each time a magazine was opened or closed. It includes information ...
3CX2500F3, it is a triode with metal ceramic structure, carbonization thorium tungsten cathode, it is cooled by the forced air, the max working frequency 75MHz, the max anode dissipation power 4kW, the tube is mainly used in industrial RF heating equipments. Electrical...
Product Description Working principle of vibration bowl feeder: frequency converter, motor, realize automatic conveying function. There is a pulse electromagnet below the hopper, which can make the hopper vibrate in the vertical direction. Due to the tilt of the spring sheet, the h...
What is the frequency (in Hz) of light emitted in the transition from n = 6 to n = 3 level in hydrogen?Hydrogen Spectrum:In the hydrogen spectrum, the transition of an electron from a higher energy level to a lower energy level produces the hydrogen emission ...
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What is frequency-dependent selection - Gromko - 1977 () Citation Context ...n in which the fitness of a phenotype depends on its frequency in the population in a 2such way that a phenotype gains advantage when its frequency decreases (i.e. negative frequency-dependence, see =-=Gromko ...
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Hi-res audio is the pinnacle for digital music fans, but what is it, how can you get it, and what kit do you need to listen to it?
High-frequency trading is atype of algorithmic trading. Traders are able to use HFT when they analyze important data to make decisions and complete trades in a matter of a few seconds. HFT facilitates large volumes of trades in a short amount of time while keeping track of market movements a...