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

easy, consider einsteins experiment for the photoelectrical effect. you take a laser and shoot it against a metal, measuring the electrical current from the metal. the energy of the current will be proportional to the energy of your laser light. since E~hf (energy = planck constant * frequency of light), you can measure plancks constant simply be finding the proportional behavior of energy and frequency of light.