Ampere second is a unit of

Options

A. Current
B. Charge
C. Energy
D. Power

Answer

To solve the question "Ampere second is a unit of," we need to analyze the options provided and determine which physical quantity corresponds to the unit "Ampere second."

### Step-by-Step Solution:

1. **Understanding the Unit "Ampere":**
- The unit "Ampere" (A) is the unit of electric current. It measures the flow of electric charge.

2. **Understanding the Unit "Second":**
- The unit "Second" (s) is the unit of time.

3. **Combining the Units:**
- The unit "Ampere second" (A·s) combines the unit of current (A) and the unit of time (s).

4. **Analyzing the Options:**
- **Option A: Current**
- Current is measured in Amperes (A). Therefore, "Ampere second" cannot be a unit of current. This option is incorrect.

- **Option B: Charge**
- Charge (Q) is defined by the equation:
\[ Q = I \cdot t \]
where \( I \) is current in Amperes and \( t \) is time in seconds.
Thus, the unit of charge is Ampere second (A·s). This option is correct.

- **Option C: Energy**
- Energy (E) can be expressed in terms of current as:
\[ E = I^2 \cdot R \cdot t \]
where \( R \) is resistance measured in Ohms (Ω). The unit of energy does not include "Ampere second," so this option is incorrect.

- **Option D: Power**
- Power (P) is given by:
\[ P = I^2 \cdot R \]
The unit of power is Watts (W), which is equivalent to Joules per second (J/s). Again, this does not include "Ampere second," making this option incorrect.

5. **Conclusion:**
- After analyzing all options, we find that "Ampere second" is indeed the unit of charge. Therefore, the correct answer is:
- **Option B: Charge.**