How can we be sure of Planck’s constant when we have never measured anything to that accuracy?

Question

Any constant in physics or chemistry comes from experimental design and consistency in measurements. For example, if you divide multiple of pressure and volume with the multiple of moles and temperature, you will get the constant R for any ideal gas.

However, given how small planck’s constant is, how can we assume its accuracy?

In: Physics

Answer 1

Many constants, including Planck’s, are not based upon physical measurements. They are derived mathematically. Just like we don’t need to physically measure a circle to the nth degree to derive the value of pi.