Search results
Results from the WOW.Com Content Network
SD g/mm 2 is the sectional density in grams per square millimeters; m g is the mass of the projectile in grams; d mm is the diameter of the projectile in millimeters; For example, a small arms bullet with a mass of 10.4 grams (160 gr) and having a diameter of 6.70 mm (0.264 in) has a sectional density of: 4 · 10.4 / (π·6.7 2) = 0.295 g/mm 2
[2] [3] Regardless of the driving force, the current density is found to be greatest at the conductor's surface, with a reduced magnitude deeper in the conductor. That decline in current density is known as the skin effect and the skin depth is a measure of the depth at which the current density falls to 1/e of its value near the surface. Over ...
[1]: 143 For example, g/cm 3 is an SI unit of density, where cm 3 is to be interpreted as (cm) 3. Prefixes are added to unit names to produce multiples and submultiples of the original unit. All of these are integer powers of ten, and above a hundred or below a hundredth all are integer powers of a thousand.
In electromagnetism, current density is the amount of charge per unit time that flows through a unit area of a chosen cross section. [1] The current density vector is defined as a vector whose magnitude is the electric current per cross-sectional area at a given point in space, its direction being that of the motion of the positive charges at this point.
The SI has special names for 22 of these coherent derived units (for example, hertz, the SI unit of measurement of frequency), but the rest merely reflect their derivation: for example, the square metre (m 2), the SI derived unit of area; and the kilogram per cubic metre (kg/m 3 or kg⋅m −3), the SI derived unit of density.
Continuous charge distribution. The volume charge density ρ is the amount of charge per unit volume (cube), surface charge density σ is amount per unit surface area (circle) with outward unit normal nĚ‚, d is the dipole moment between two point charges, the volume density of these is the polarization density P.
Get AOL Mail for FREE! Manage your email like never before with travel, photo & document views. Personalize your inbox with themes & tabs. You've Got Mail!
Pd = H 2 × 377 and Pd = E 2 ÷ 377 where Pd is the power density in watts per square meter (one W/m 2 is equal to 0.1 mW/cm 2), H 2 = the square of the value of the magnetic field in amperes RMS squared per meter squared, E 2 = the square of the value of the electric field in volts RMS squared per meter squared. [6]