Physics 2 · Reference

Units and constants

2 min read

On this page 2 sections

The college version

Quantity	Unit	Symbol	Equivalent
Force	newton	N	kg·m/s²
Energy, work, heat	joule	J	N·m
Power	watt	W	J/s
Pressure	pascal	Pa	N/m²
Electric charge	coulomb	C	A·s
Voltage, potential	volt	V	J/C
Resistance	ohm	Ω	V/A
Capacitance	farad	F	C/V
Magnetic field	tesla	T	N/(A·m)
Magnetic flux	weber	Wb	T·m²
Inductance	henry	H	V·s/A
Frequency	hertz	Hz	s⁻¹

Constant	Symbol	Value	Notes
Speed of light in vacuum	c	2.998 × 10⁸ m/s	Exact defined value: 299,792,458 m/s
Elementary charge	e	1.602 × 10^-19 C	Approximate
Gravitational acceleration (Earth surface)	g	9.80 m/s²	Approximate; varies slightly with location
Gravitational constant	G	6.674 × 10^-11 N·m²/kg²	Experimentally determined
Coulomb's constant	k	8.988 × 10⁹ N·m²/C²	k = 1/(4πε₀)
Permittivity of free space	ε₀	8.854 × 10^-12 C²/(N·m²)	Exact defined
Permeability of free space	μ₀	4π × 10^-7 T·m/A	Exact defined
Planck's constant	h	6.626 × 10^-34 J·s	Experimentally determined
Boltzmann constant	k_B	1.381 × 10^-23 J/K	Approximate
Universal gas constant	R	8.314 J/(mol·K)	R = N_A k_B
Avogadro's number	N_A	6.022 × 10²³ mol^-1	Approximate
Electron mass	m_e	9.109 × 10^-31 kg	Approximate
Proton mass	m_p	1.673 × 10^-27 kg	Approximate
Standard atmospheric pressure	P_atm	1.013 × 10⁵ Pa	At sea level

[ T_K = T_C + 273.15 ] [ T_F = \frac{9}{5}T_C + 32 ]

You’ve reached the end of this chapter. Return to the outline to choose what to explore next.

This lesson has no separate scored set. Practice draws from the subject’s question bank.

Study tools & related lessonsRelated

Educational content only. It is not medical, legal or professional advice. Found an error? Tell us.