Question

The unit of Planck’s constant is equivalent to that of:
A) Energy
B) Angular momentum
C) Velocity
D) Force

Answer 1

Hint: The planck’s constant is defined as the energy per unit frequency. This gives the physical quantity of angular momentum. The angular momentum is the product of radius and linear momentum.

Complete step by step answer:
The unit of planck’s constant is equivalent to that of angular momentum. Their dimensional formulas are the same but both physical quantities are not the same. Planck’s constant gives the relation between energy and frequency. The formula which expresses this relation is $E = h\nu $. The value of $h = 6.626 \times {10^{ - 34}}{m^2}kg{s^{ - 1}}$. Whereas the angular momentum is the rotational equivalent of linear momentum. It is an important physical quantity because it is a conserved quantity.

For a rotating body the angular momentum of a closed system remains constant. Both physical quantities have the same unit but have different significance. Planck’s constant is the amount of energy a photon carries with the frequency of its electromagnetic wave. The value for Planck's constant is the slope of a graph multiplied by e/c where e is electronic charge and c is speed of light.

Note: The planck's constant is the energy in a photon. So it does not mean that it will be equivalent to energy. Either it have same unit as that of angular momentum. Therefore it has the same unit as angular momentum.