Couldn't tell you. Can't even find a clear, straight forward definition of what it is.
"Planck’s constant, (symbol h), fundamental physical constant characteristic of the mathematical formulations of quantum mechanics, which describes the behaviour of particles and waves on the atomic scale, including the particle aspect of light.
The German physicist Max Planck introduced the constant in 1900 in his accurate formulation of the distribution of the radiation emitted by a blackbody, or perfect absorber of radiant energy (see Planck’s radiation law). The significance of Planck’s constant in this context is that radiation, such as light, is emitted, transmitted, and absorbed in discrete energy packets, or quanta, determined by the frequency of the radiation and the value of Planck’s constant.
The energy E of each quantum, or each photon, equals Planck’s constant h times the radiation frequency symbolized by the Greek letter nu, ν, or simply E = hν. A modified form of Planck’s constant called h-bar (ℏ), or the reduced Planck’s constant, in which ℏ equals h divided by 2π, is the quantization of angular momentum. For example, the angular momentum of an electron bound to an atomic nucleus is quantized and can only be a multiple of h-bar.
The dimension of Planck’s constant is the product of energy multiplied by time, a quantity called action. Planck’s constant is often defined, therefore, as the elementary quantum of action. Its value in metre-kilogram-second units is 6.62606957 × 10^−34 joules/second, with a standard uncertainty of 0.00000029 × 10^−34 joules/second.
http://www.britannica.com/EBchecked/topic/462917/Plancks-constant
A simplified explanation of Planck’s constant:
Imagine that you are pouring water into a pan, and you discover that, rather than flowing as a continuous stream, the water was actually composed of droplets so small that they looked like a stream. No matter how fast or slowly you poured, the water always came out in droplets.
So you tried to pour out as little water as you could, to see if you could get a half of a droplet, or a quarter-droplet, etc. What you find is that tipping out the water, either none comes out, or a single droplet, or multiples of that single droplet. So it turns out that water has a minimum sized droplet that can be poured out. So we’d like to measure the size of that droplet, so that I can now describe the amount of water poured out in terms of the number of droplets.
Now, this is not true for water (unless we are talking water molecules themselves). But it IS true for energy. Energy can only be released or absorbed in “droplets” (known as “quanta”). And Planck’s constant helps describe the minimum size those “droplets” of energy can be.
Make sense?