If `I` is the intenisty of an absorbed light and `c` is the concentration of `AB` for the photochemical process. `AB+hv rarr AB^(**)`, the rate of formation of `AB^(**)` is directly proportional to

Options

A. `c`
B. `I`
C. `I^(2)`
D. `c xx I`

Explanation

To solve the question regarding the photochemical process where \( AB + hv \rightarrow AB^{**} \), we need to determine what the rate of formation of \( AB^{**} \) is directly proportional to.

### Step-by-Step Solution:

1. **Understanding the Reaction**:
The given reaction is a photochemical reaction where \( AB \) absorbs light energy (denoted by \( hv \)) and gets converted into an excited state \( AB^{**} \).

2. **Identifying Factors Affecting the Rate**:
In photochemical reactions, the rate of formation of products is influenced by two main factors:
- The intensity of the light (\( I \))
- The concentration of the reactant (\( c \))

3. **Analyzing the Role of Light Intensity**:
- The intensity of the absorbed light (\( I \)) directly affects the energy available for the reaction. Higher intensity means more photons are available to excite the reactant \( AB \).
- Therefore, as the intensity of light increases, more \( AB \) molecules can be excited to form \( AB^{**} \).

4. **Analyzing the Role of Concentration**:
- The concentration of \( AB \) (\( c \)) also plays a crucial role. Higher concentration means more \( AB \) molecules are available to react with the absorbed light.

5. **Conclusion**:
The rate of formation of \( AB^{**} \) is directly proportional to both the intensity of the absorbed light (\( I \)) and the concentration of \( AB \) (\( c \)). However, since the question specifically asks for what it is directly proportional to, we can conclude that the rate is primarily influenced by the intensity of the light.

Thus, the rate of formation of \( AB^{**} \) is directly proportional to the intensity of the absorbed light (\( I \)).

### Final Answer:
The rate of formation of \( AB^{**} \) is directly proportional to the intensity of the absorbed light (\( I \)).