Derived Planck Units
In any system of measurement, units for many physical quantities can be derived from base units. Table 3 offers a sample of derived Planck units, some of which in fact are seldom used. As with the base units, their use is mostly confined to theoretical physics because most of them are too large or too small for empirical or practical use and there are large uncertainties in their values (see Discussion and Uncertainties in values below).
| Name | Dimension | Expression | Approximate SI equivalent |
|---|---|---|---|
| Planck area | Area (L2) | 2.61223 × 10−70 m2 | |
| Planck volume | Volume (L3) | 4.22419 × 10−105 m3 | |
| Planck momentum | Momentum (LMT−1) | 6.52485 kg m/s | |
| Planck energy | Energy (L2MT−2) | 1.9561 × 109 J | |
| Planck force | Force (LMT−2) | 1.21027 × 1044 N | |
| Planck power | Power (L2MT−3) | 3.62831 × 1052 W | |
| Planck density | Density (L−3M) | 5.15500 × 1096 kg/m3 | |
| Planck angular frequency | Frequency (T−1) | 1.85487 × 1043 s−1 | |
| Planck pressure | Pressure (L−1MT−2) | 4.63309 × 10113 Pa | |
| Planck current | Electric current (QT−1) | 3.4789 × 1025 A | |
| Planck voltage | Voltage (L²MT−2Q−1) | 1.04295 × 1027 V | |
| Planck impedance | Resistance (L2MT−1Q−2) | 29.9792458 Ω |
Read more about this topic: Planck Units
Famous quotes containing the words derived and/or units:
“If all political power be derived only from Adam, and be to descend only to his successive heirs, by the ordinance of God and divine institution, this is a right antecedent and paramount to all government; and therefore the positive laws of men cannot determine that, which is itself the foundation of all law and government, and is to receive its rule only from the law of God and nature.”
—John Locke (1632–1704)
“Even in harmonious families there is this double life: the group life, which is the one we can observe in our neighbour’s household, and, underneath, another—secret and passionate and intense—which is the real life that stamps the faces and gives character to the voices of our friends. Always in his mind each member of these social units is escaping, running away, trying to break the net which circumstances and his own affections have woven about him.”
—Willa Cather (1873–1947)