Force: basic, 126 electromagnetic

According to our current knowledge, there exist four basic types of forces gravitational, electromagnetic, strong, and weak. The electromagnetic force is the force that binds the electrons and the nuclei inside the atom, and the atoms inside a molecule, and that governs the interaction between atoms and molecules. These are referred to as the so-called intermolecular interactions [92-94,186,187]. Indeed,... 

The thermal-convection loops are limited to flow velocities up to about 6 cm s . Where higher velocities are required, the liquid must be pumped, either mechanically or electromagnetically the latter is usually preferred as it avoids the problem of leakage at the pump seal. Basically, these forced-convection systemsconsist of (c) a hot leg, where the liquid metal is... 

It was also believed that there were three basic forces in nature gravity, electromagnetism, and a force that caused the particles within the nucleus to stick together. No one knew what kind of force the last... 

In this section we discuss the interaction between an electric field and a charge that is free to move with the field. Such a charge experiences a force that accelerates it with the field. If the field is oscillating, the acceleration of the charge will also oscillate. One of the basic results of classical electromagnetics is that the acceleration of a charge leads to the emission of radiation. 

The SI equations of electromagnetic theory are usually used with physical quantities in SI units, in particular the four units m, kg, s, and A for length, mass, time and electric current. The basic equations for the electrostatic force between charges Qx and Q2, and for the electromagnetic force between current elements It dlx and I2 d/2, in vacuum, are written... 

The overall precision is not limited by the quality of the force measurement. Several sensitive and accurate tensiometers are available, some commercially, the well-known Cahn electrobalance being one of these. The force measurement is based on a few basic principles, like the torsion of a wire or electromagnetic feedback. Of these the former is obsolete nowadays. However, an everyday good, analytical balance is also adequate. 

But this is likely to be the exception. At any rate, in the case of carbon, recent calculations seem to indicate that the fine-tuning first apparent in the chemistry of the various nuclei involved carries over to the level of basic physics were the strong force to be greater by as little as 5 percent, or the electromagnetic force to be greater by perhaps 4 percent, the production of carbon and oxygen in the infant universe could have shut down. " ... 

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