Azimuthal quantum number defines.

Options

A. e/m ratio of electron
B. angular momentum of electron
C. spin of electron
D. magnetic momentum of electron .

Explanation

To solve the question regarding what the azimuthal quantum number defines, we will follow these steps:

### Step 1: Understand the Azimuthal Quantum Number
The azimuthal quantum number, also known as the orbital angular momentum quantum number, is a quantum number that describes the shape of an atomic orbital and its angular momentum.

**Hint:** Remember that the azimuthal quantum number is associated with the shape of the orbital.

### Step 2: Identify the Symbol and Range
The azimuthal quantum number is denoted by the symbol \( l \) and can take on integer values from \( 0 \) to \( n-1 \), where \( n \) is the principal quantum number.

**Hint:** The values of \( l \) correspond to different types of orbitals: \( l=0 \) for s, \( l=1 \) for p, \( l=2 \) for d, and \( l=3 \) for f orbitals.

### Step 3: Relate to Angular Momentum
The azimuthal quantum number is directly related to the angular momentum of the electron in an atom. The angular momentum \( L \) can be calculated using the formula:
\[ L = \sqrt{l(l+1)} \cdot \frac{h}{2\pi} \]
where \( h \) is Planck's constant.

**Hint:** The angular momentum is a key aspect of the azimuthal quantum number.

### Step 4: Analyze the Options
Now we will analyze the options given in the question:
1. E/m ratio of electron: This refers to the charge-to-mass ratio, which is not defined by the azimuthal quantum number.
2. Angular momentum of the electron: This is indeed defined by the azimuthal quantum number.
3. Spin of electron: This is defined by a different quantum number (the spin quantum number).
4. Magnetic moment of the electron: This is related but not directly defined by the azimuthal quantum number.

**Hint:** Focus on the definitions provided and match them with the correct quantum number.

### Step 5: Conclusion
Based on the analysis, the azimuthal quantum number primarily defines the angular momentum of the electron.

**Final Answer:** The azimuthal quantum number defines the angular momentum of the electron.