# Planck's constant

1. Oct 14, 2013

### Numeriprimi

Hello,
is there anyone who can explain me difference between the reduced Planck's constant and Planck's constant? SIMPLY. I know equation between this but... I don't understand it.

If I express the Planck's length by √(hG/c), it is bad? There have to be reducet Planck's constant, bud why?

Thanks very much,

2. Oct 14, 2013

### DrewD

The reduced Planck Constant is just the original divided by $2\pi$. There is no meaning. Since the equations often turned up with this factor dividing the constant, $\hbar$ is often used to simplify notation.

3. Oct 14, 2013

### dauto

To add to what DrewD said (which is correct) also note that it would not be bad to define the Planck length in terms of the Planck constant instead of the reduced Planck constant. We chose to use the reduced constant instead of the plain Planck constant for the convenience of simpler equations, but it is still just a convention. Other choices are not bad.