SI Base & Derived Units Flashcards

SI Base & Derived Units flashcards — the free 29

Every question and answer on the free cards, written out. Check them against your own textbook before you spend anything.

The second (s)

Time — fixed by the caesium-133 hyperfine frequency ΔνCs = 9 192 631 770 Hz

The metre (m)

Length — fixed by the speed of light c = 299 792 458 m/s (US spelling: meter)

The kilogram (kg)

Mass — fixed by the Planck constant h = 6.626 070 15×10⁻³⁴ J s, not by any metal prototype

The ampere (A)

Electric current — fixed by the elementary charge e = 1.602 176 634×10⁻¹⁹ C

The kelvin (K)

Thermodynamic temperature — fixed by the Boltzmann constant k = 1.380 649×10⁻²³ J/K

The mole (mol)

Amount of substance — exactly 6.022 140 76×10²³ elementary entities (the Avogadro number)

The candela (cd)

Luminous intensity — fixed by Kcd = 683 lm/W for radiation of frequency 540×10¹² Hz

The radian (rad)

Plane angle — expressed as 1. The angle whose arc equals the radius; m/m is misleading, per BIPM

The steradian (sr)

Solid angle — expressed as 1. A whole sphere subtends 4π sr; m²/m² is misleading, per BIPM

The hertz (Hz)

Frequency — s⁻¹. For periodic phenomena only; for radionuclides use the becquerel

The newton (N)

Force — kg m s⁻²

The pascal (Pa)

Pressure and stress — N/m² = kg m⁻¹ s⁻²

The joule (J)

Energy, work and heat — N m = kg m² s⁻²

The watt (W)

Power and radiant flux — J/s = kg m² s⁻³

The coulomb (C)

Electric charge — A s

The volt (V)

Electric potential difference — W/A = kg m² s⁻³ A⁻¹

The farad (F)

Capacitance — C/V = kg⁻¹ m⁻² s⁴ A²

The ohm (Ω)

Electric resistance — V/A = kg m² s⁻³ A⁻²

The siemens (S)

Electric conductance — A/V = kg⁻¹ m⁻² s³ A²

The weber (Wb)

Magnetic flux — V s = kg m² s⁻² A⁻¹

The tesla (T)

Magnetic flux density — Wb/m² = kg s⁻² A⁻¹

The henry (H)

Inductance — Wb/A = kg m² s⁻² A⁻²

The degree Celsius (°C)

Celsius temperature — the same size as the kelvin: t/°C = T/K − 273.15

The lumen (lm)

Luminous flux — cd sr

The lux (lx)

Illuminance — lm/m² = cd sr m⁻²

The becquerel (Bq)

Activity referred to a radionuclide — s⁻¹. For stochastic decay only, never for frequency

The gray (Gy)

Absorbed dose and kerma — J/kg = m² s⁻²

The sievert (Sv)

Dose equivalent — J/kg = m² s⁻². Same dimensions as the gray, different quantity

The katal (kat)

Catalytic activity — mol s⁻¹

SI Base & Derived Units flashcards — questions people ask

How many cards are in the SI Base & Derived Units flashcard deck?

The SI Base & Derived Units deck on PuzzlePage has 29 cards, and all 29 are free to play and free to download with no account and no payment. 29 cards, because the SI has exactly seven base units and exactly 22 coherent derived units with special names. The BIPM's own words: together they 'form the core of the set of SI units', and all other SI units are combinations of these 29. The number is fixed by the SI, not chosen to fill a deck.

What is on the si base & derived units flashcards?

All 29 named SI units — the seven base units, each fixed by a constant of nature since 2019, and the 22 derived ones. Companion to the physics-formulas deck. Cards look like this: The second (s) → Time — fixed by the caesium-133 hyperfine frequency ΔνCs = 9 192 631 770 Hz; The metre (m) → Length — fixed by the speed of light c = 299 792 458 m/s (US spelling: meter). The deck is written for grades 9–12 and filed under science.

Can I study si base & derived units flashcards online for free?

Yes. All 29 cards of the SI Base & Derived Units deck play free in any web browser at puzzlepage.app, with no account, no app and no card details. It works on a phone, tablet, Chromebook, laptop or classroom projector. Practice mode flips through the cards with nothing scored; quiz mode makes you answer each card before it flips, times the run and scores it.

Are the si base & derived units flashcards accurate?

Every card in the SI Base & Derived Units deck cites two independent published sources — two different organisations, not a standards body and a site reprinting it — and a script checks that, rather than taking the writer's word for it. A second specialist then re-verified the deck against sources of their own, without reading the citations first. That is the difference from a user-generated flashcard site, where the cards are whatever a stranger typed and nobody is accountable for them.

Can I print the si base & derived units flashcards?

Yes. The SI Base & Derived Units cards are available as a printable double-sided PDF to cut up, as well as playable in the browser. The whole 29-card printable is free to download, with no account.

How should I use the SI Base & Derived Units deck to revise?

Start in practice mode and go through the SI Base & Derived Units deck once without scoring, to find out which cards you already know — the deck is dealt in a different order every time you open it, so you are recalling the card rather than its position. Then switch to quiz mode, which times and scores the run and lets you re-run only the cards you missed. Use the "flip deck" control to swap which side is the question: recognising an answer is much easier than producing one, so a deck you find easy one way round is usually the harder and more useful drill the other way. Two or three short sessions across a week beat one long one, which is the whole reason flashcards work.

What grade level are the si base & derived units flashcards for?

The SI Base & Derived Units deck is written for grades 9–12. Because the cards are plain term-and-answer pairs, they are also used outside that band — by adults revising science, and by teachers running them as a whole-class starter on a projector.