Linear expansivity is the fractional increase in length of a specimen of a solid, per unit rise in temperature. ... Superficial expansivity is the fractional increase in area of a solid surface caused by unit rise in temperature, i.e. A2 = A1(1 + βθ), where β is the superficial expansivity.
Linear expansivity is the fractional increase in length of a specimen of a solid, per unit rise in temperature. If a specimen increases in length from l1 to l2 when its temperature is raised θ°, then the expansivity (α) is given by: l2 = l1(1 + αθ). This relationship assumes that α is independent of temperature. This is not, in general, the case and a more accurate relationship is: l2 = l1(1 + aθ + bθ2 + cθ3…), where a, b, and c are constants.
The difference between them is in regard to what spins and what is fixed. In an alternator<span>, electricity is produced when a magnetic field spins inside the stator (windings of wired) </span>
