NUC-17

Radioactivity units

1 Ci = 3.7×10¹⁰ Bq. Historical unit versus the SI becquerel.

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DecaySI becquerel

Governing equation

A_{\mathrm{Bq}}=3.7\times 10^{10}\,A_{\mathrm{Ci}}

$A \in \left[1\times 10^{-9}, 100\right]$

where

A: Activity (Ci)
A: Becquerel (Bq)
A: Megabecquerel (MBq)

The figure, part by part

Each numbered marker wears the color of its card. Hover a card to light the marker. Tap a marker to jump to that card. The slider walks a red point along the curve; Animate drawing traces it like a pen.

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①

Governing law — red

A_{\mathrm{Bq}}=3.7\times 10^{10}\,A_{\mathrm{Ci}}

$A \in \left[1\times 10^{-9}, 100\right]$

$A = 1\times 10^{-9}$ $A = 37$

Along the curve

②

Domain of the variable — blue

A_{\min} = 1\times 10^{-9},\quad A_{\max} = 100

$A \in \left[1\times 10^{-9}, 100\right]$

$A = 1\times 10^{-9}$ $A = 1\times 10^{-9}$

Along the curve

③

Response curve — green

A_{\mathrm{Bq}}=3.7\times 10^{10}\,A_{\mathrm{Ci}}

$A \in \left[1\times 10^{-9}, 100\right]$

$A = 1\times 10^{-9}$ $A = 37$

Along the curve

④

Rate of change — amber

\frac{\mathrm{d}A}{\mathrm{d}A}

$A \in \left[1\times 10^{-9}, 100\right]$

$A = 0.629$ $A^{\prime} = 3.7\times 10^{10}$

Along the curve

Lecture brief

Historical brief

Rutherford, Chadwick, the semi-empirical mass formula, fission (Hahn–Strassmann 1938) and fusion Q-values, then Compton and Bethe–Bloch stopping, are the nuclear toolkit. Decay, binding and dose start here. This sheet (NUC-17 — Radioactivity units) is the form associated with SI becquerel. Working symbols: $A$ $\rightarrow$ $A$ , $A$ . 1 Bq = 1 s⁻¹. Specific activity a = λ N_A / M for a pure isotope.

Purpose

Purpose: compute

A

A

from

A

in Nuclear physics via

A_{\mathrm{Bq}}=3.7\times 10^{10}\,A_{\mathrm{Ci}}

1 Ci = 3.7×10¹⁰ Bq. Historical unit versus the SI becquerel. Use it when a real nuclear physics question must be answered in SI before a code check.

Live realistic example

In symbols

Live case. Given

A = 0.001\,\mathrm{Ci}

, the governing relation

A_{\mathrm{Bq}}=3.7\times 10^{10}\,A_{\mathrm{Ci}}

yields

A = 3.70e+7\,\mathrm{Bq}

A = 37.000\,\mathrm{MBq}

. A sample labelled in Ci and Bq. Move a slider: the numbers are this situation, not a canned story.

Calculator

Inputs

Activity A0.001 Ci

Outputs

Becquerel A37000000.00 Bq
Megabecquerel A37.000 MBq

Reading speed

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Narration of this film

A sample labelled in Ci and Bq.

1 Bq = 1 s⁻¹. Specific activity a = λ N_A / M for a pure isotope.

Reading speed

Watch on YouTube