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# U+210FPlanck Constant Over Two Pi

U+210F was added in Unicode version 1.1 in 1993. It belongs to the block U+2100 to U+214F Letterlike Symbols in the U+0000 to U+FFFF Basic Multilingual Plane.

This character is a Lowercase Letter and is commonly used, that is, in no specific script. The character is also known as reduced Planck constant and Dirac constant.

The glyph is a font version of the glyph Latin Small Letter H with Stroke. It has no designated width in East Asian texts. In bidirectional text it is written from left to right. When changing direction it is not mirrored. The word that U+210F forms with similar adjacent characters prevents a line break inside it. The glyph can be confused with one other glyph.

The Planck constant, or Planck's constant, denoted by $h$, is a fundamental physical constant of foundational importance in quantum mechanics: a photon's energy is equal to its frequency multiplied by the Planck constant, and the wavelength of a matter wave equals the Planck constant divided by the associated particle momentum.

The constant was postulated by Max Planck in 1900 as a proportionality constant needed to explain experimental black-body radiation. Planck later referred to the constant as the "quantum of action". In 1905, Albert Einstein associated the "quantum" or minimal element of the energy to the electromagnetic wave itself. Max Planck received the 1918 Nobel Prize in Physics "in recognition of the services he rendered to the advancement of Physics by his discovery of energy quanta".

In metrology, the Planck constant is used, together with other constants, to define the kilogram, the SI unit of mass. The SI units are defined in such a way that, when the Planck constant is expressed in SI units, it has the exact value $h$ = 6.62607015×10−34 J⋅Hz−1. It is often used with units of electronvolt (eV), which corresponds to the SI unit per elementary charge.

## Representations

System Representation
8463
UTF-8 E2 84 8F
UTF-16 21 0F
UTF-32 00 00 21 0F
URL-Quoted %E2%84%8F
HTML hex reference &#x210F;
Wrong windows-1252 Mojibake â„
HTML named entity &hbar;
HTML named entity &hslash;
HTML named entity &planck;
HTML named entity &plankv;
alias reduced Planck constant
alias Dirac constant
LATEX \hslash

## Complete Record

Property Value
Age (age) 1.1 (1993)
Unicode Name (na) PLANCK CONSTANT OVER TWO PI
Unicode 1 Name (na1) PLANCK CONSTANT OVER 2 PI
Block (blk) Letterlike Symbols
General Category (gc) Lowercase Letter
Script (sc) Common
Bidirectional Category (bc) Left To Right
Combining Class (ccc) Not Reordered
Decomposition Type (dt) font
Decomposition Mapping (dm) Latin Small Letter H with Stroke
Lowercase (Lower)
Simple Lowercase Mapping (slc) Planck Constant Over Two Pi
Lowercase Mapping (lc) Planck Constant Over Two Pi
Uppercase (Upper)
Simple Uppercase Mapping (suc) Planck Constant Over Two Pi
Uppercase Mapping (uc) Planck Constant Over Two Pi
Simple Titlecase Mapping (stc) Planck Constant Over Two Pi
Titlecase Mapping (tc) Planck Constant Over Two Pi
Case Folding (cf) Planck Constant Over Two Pi
ASCII Hex Digit (AHex)
Alphabetic (Alpha)
Bidi Control (Bidi_C)
Bidi Mirrored (Bidi_M)
Composition Exclusion (CE)
Case Ignorable (CI)
Changes When Casefolded (CWCF)
Changes When Casemapped (CWCM)
Changes When NFKC Casefolded (CWKCF)
Changes When Lowercased (CWL)
Changes When Titlecased (CWT)
Changes When Uppercased (CWU)
Cased (Cased)
Full Composition Exclusion (Comp_Ex)
Default Ignorable Code Point (DI)
Dash (Dash)
Deprecated (Dep)
Diacritic (Dia)
Emoji Modifier Base (EBase)
Emoji Component (EComp)
Emoji Modifier (EMod)
Emoji Presentation (EPres)
Emoji (Emoji)
Extender (Ext)
Extended Pictographic (ExtPict)
FC NFKC Closure (FC_NFKC) Planck Constant Over Two Pi
Grapheme Cluster Break (GCB) Any
Grapheme Base (Gr_Base)
Grapheme Extend (Gr_Ext)
Hex Digit (Hex)
Hyphen (Hyphen)
ID Continue (IDC)
ID Start (IDS)
IDS Binary Operator (IDSB)
IDS Trinary Operator and (IDST)
IDSU (IDSU) 0
ID_Compat_Math_Continue (ID_Compat_Math_Continue) 0
ID_Compat_Math_Start (ID_Compat_Math_Start) 0
Ideographic (Ideo)
InCB (InCB) None
Indic Mantra Category (InMC)
Indic Positional Category (InPC) NA
Indic Syllabic Category (InSC) Other
Jamo Short Name (JSN)
Join Control (Join_C)
Logical Order Exception (LOE)
Math (Math)
Noncharacter Code Point (NChar)
NFC Quick Check (NFC_QC) Yes
NFD Quick Check (NFD_QC) Yes
NFKC Casefold (NFKC_CF) Latin Small Letter H with Stroke
NFKC Quick Check (NFKC_QC) No
NFKC_SCF (NFKC_SCF) Latin Small Letter H with Stroke
NFKD Quick Check (NFKD_QC) No
Other Alphabetic (OAlpha)
Other Default Ignorable Code Point (ODI)
Other Grapheme Extend (OGr_Ext)
Other ID Continue (OIDC)
Other ID Start (OIDS)
Other Lowercase (OLower)
Other Math (OMath)
Other Uppercase (OUpper)
Prepended Concatenation Mark (PCM)
Pattern Syntax (Pat_Syn)
Pattern White Space (Pat_WS)
Quotation Mark (QMark)
Regional Indicator (RI)
Sentence Break (SB) Lower
Soft Dotted (SD)
Sentence Terminal (STerm)
Terminal Punctuation (Term)
Unified Ideograph (UIdeo)
Variation Selector (VS)
Word Break (WB) Alphabetic Letter
White Space (WSpace)
XID Continue (XIDC)
XID Start (XIDS)
Expands On NFC (XO_NFC)
Expands On NFD (XO_NFD)
Expands On NFKC (XO_NFKC)
Expands On NFKD (XO_NFKD)
Bidi Paired Bracket (bpb) Planck Constant Over Two Pi
Bidi Paired Bracket Type (bpt) None
East Asian Width (ea) neutral
Hangul Syllable Type (hst) Not Applicable
ISO 10646 Comment (isc)
Joining Group (jg) No_Joining_Group
Joining Type (jt) Non Joining
Line Break (lb) Alphabetic
Numeric Type (nt) none
Numeric Value (nv) not a number
Simple Case Folding (scf) Planck Constant Over Two Pi
Script Extension (scx)
Vertical Orientation (vo) U