Description

The calculator expresses dimensionful quantity X in desired units.

Write expression for X in the upper field of the calculator and desired units in the lower field. Press the button "Compute" and obtain the result in the form
X = number [units] ^power,
where "number" and "power" are computed by the calculator; "units" are taken from the lower field.

In the fields of the calculator one uses:

• - arithmetic operations +, -, *, /;
• - power-raising operation x^y = x**y;
• - brackets ();
• - simple functions sqrt(), exp(), log(), sin(), cos(), asin(), sinh(), cosh();
• - units listed in the right column.

Importantly, the physical quantities are represented as numbers multiplied by units. For example, energy 2 GeV is written as "2.0*GeV". Also, one should always explicitly write the fractional part of a number: use "1.0" for "1", "2.0" for "2", etc.

Example 1. To express the quantity \( \sqrt{2\mbox{J}\cdot 3\mbox{К}}\) in GigaElectronVolts, write "(2.0*J*3.0*K)**0.5" in the upper field and "GeV" in the lower field. Press "Compute".

Example 2. To compute dimensionless quantities, one uses "1" in the lower field. In particular, quantity \(\mbox{cm}/\mbox{s}\) is expressed in universal units by writing "cm/s" and "1" in the upper and lower fields, respectively.

Warning. The calculator cannot express the quantity with nontrivial dimension in the system \(\hbar = c = k_B = 1\) into dimensionless units and vise versa. Also, the arguments of functions exp(), log(), sin(), etc., should be dimensionless, otherwise the calculation does not make any sense. In all cases explicitly write the fractional part of a number: "5.0" or "5.0e+01" instead of "5".

Note also that the calculator uses Gaussian electric units, like the Landau-Lifshitz textbook. In particular, \( e^2 = 1/137\). Transition to Heaviside units: \( {e}_{\rm Heaviside} = \sqrt{4\pi}\; e_{\rm Gauss}\),    \( E_{\rm Heaviside} = E_{\rm Gauss} / \sqrt{4\pi}\), where \(E\) is an electromagnetic potential, electric or magnetic field strength.