The unit of charge is coulomb in SI system and esu of charge (or stat coul) in C.G.S. system 1 coulomb equals

Options

A. `(3 xx 10^(9))` esu
B. `(1//3 xx 10^(9))` esu
C. `(1//3 xx 10^(8))` esu
D. `(9 xx 10^(9))` esu

Answer

To find the relationship between the SI unit of charge (coulomb) and the CGS unit of charge (stat coulomb or electrostatic unit of charge), we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Units**:
- The SI unit of charge is the coulomb (C).
- The CGS unit of charge is the electrostatic unit of charge (esu), also known as stat coulomb (stat C).

2. **Conversion Factor**:
- It is known from electrostatics that 1 coulomb is equivalent to a certain number of stat coulombs.

3. **Using the Known Value**:
- The relationship between coulombs and stat coulombs is given by:
\[ 1 \text{ C} = 2.99 \times 10^9 \text{ stat C} \]

4. **Final Expression**:
- Therefore, we can conclude that:
\[ 1 \text{ C} \approx 3 \times 10^9 \text{ esu} \]

### Final Answer:
1 coulomb is equal to approximately \( 3 \times 10^9 \) stat coulombs (esu).

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