According to Bohr second postulate, the angular momentum of electron is the integral multiple of `h/(2pi)` . The S.I unit of Plank constant h is same as……

Options

A. Linear momentum
B. angular momentum
C. Energy
D. Centripetal force

Answer

To determine the SI unit of Planck's constant \( h \), we need to relate it to the concept of angular momentum as stated in Bohr's second postulate. Here’s a step-by-step solution:

### Step 1: Understand Bohr's Second Postulate
According to Bohr's second postulate, the angular momentum \( L \) of an electron in an orbit is quantized and is given by:
\[ L = n \frac{h}{2\pi} \]
where \( n \) is an integer (the quantum number), and \( h \) is Planck's constant.

### Step 2: Identify the Unit of Angular Momentum
The angular momentum \( L \) can be expressed in terms of its fundamental units. The formula for angular momentum is:
\[ L = mvr \]
where:
- \( m \) is the mass of the electron (in kg),
- \( v \) is the linear velocity (in m/s),
- \( r \) is the radius of the orbit (in meters).

The SI unit of angular momentum is:
\[ \text{Angular Momentum} = \text{kg} \cdot \text{m}^2/\text{s} \]

### Step 3: Relate Planck's Constant to Angular Momentum
From Bohr's postulate, we see that the angular momentum is proportional to Planck's constant. Therefore, the unit of Planck's constant \( h \) must be the same as the unit of angular momentum.

### Step 4: Conclusion
Thus, the SI unit of Planck's constant \( h \) is:
\[ \text{kg} \cdot \text{m}^2/\text{s} \]

### Final Answer
The SI unit of Planck's constant \( h \) is the same as the unit of angular momentum, which is \( \text{kg} \cdot \text{m}^2/\text{s} \).

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