Use a physical constant in a formula
Enter constants such as the speed of light correctly, store them for reuse, and see them in the Units lab.
These calculators do not have a table of constants, so you type the value yourself in scientific notation. Take a constant from your textbook or the app, and keep all its digits.
Example: the energy in 1 gram of matter is E = mc². With m = 0.001 kg and c = 2.99792458 × 10⁸ m/s, the answer is about 8.99 × 10¹³ joules.
- The Units lab (a Reference lab) has a constants library with the speed of light, Planck constant, Avogadro number, gas constant and more. Open it from the Reference library.
- In the lab you can also type a unit-aware expression such as 1 g * [c]^2 to J and it returns the energy with its unit.
Classic Graphing 84
Start on the main screen: Press 2nd then mode (QUIT) to get back to the home screen. Pressing clear on a menu also backs out of it.
Type the constant c in scientific notation, press STO→, then ALPHA and the key printed C (the PRGM key), and press enter. It is now stored in the variable C.
2.997924582ndEE,8sto→alphaCprgmenterType .001 × C² : use ALPHA and the same key for C, then x². Press enter.
.001×alphaCprgmx²enter
You should see8.987551787E13
Natural Scientific 991
Start on the main screen: Press MENU, then 1 (Calculate) to return to the main calculation screen. AC clears the line you are on.
Type .001 × then open a bracket and type c using the ×10ˣ key: 2.99792458 ×10ˣ 8. Close the bracket and square it.
.001×(2.99792458×10ˣ8)x²Press = . The brackets matter: without them only 8 would be squared.
=
You should see8.987551787×10^13
RPN Scientific 15
Start on the main screen: There is no menu to leave. Press the back arrow to clear a number you are typing, or CLx (g then back arrow) to clear the X register.
Key in the constant: 2.99792458, EEX, 8. Square it with g and x² (the √x key).
2.99792458EEX8gx²√xKey in .001 and press × . The display switches to scientific by itself.
.001×
You should see8.9876 13
Tips
- Store a constant you use often in a variable, as on the 84 above. Typing it once avoids mistakes.
- Keep at least one more digit than your answer needs, then round at the end.
Related guides
- Enter very big and very small numbersType numbers like 6.022 × 10²³ with the exponent key and read answers shown in scientific notation.
- Store a number in a variableSave a value under a letter so you can use it again in later calculations.
- Convert between unitsChange miles per hour to metres per second (or any unit) by multiplying by conversion factors.