Which of the following is the ratio of drift velocity concerning the electric field ?

Options

A. Coulomb's Law.
B. Mobility
C. Faraday's Law
D. Ampere Law

Explanation

To solve the question regarding the ratio of drift velocity concerning the electric field, we can follow these steps:

### Step 1: Understand the Definitions
- **Drift Velocity (Vd)**: This is the average velocity that a charge carrier, such as an electron, attains due to an electric field.
- **Electric Field (E)**: This is a field around charged particles that exerts a force on other charged particles.

### Step 2: Identify the Relationship
The relationship between drift velocity and electric field is given by the formula:
\[ V_d = \mu E \]
where:
- \( V_d \) is the drift velocity,
- \( \mu \) is the mobility of the charge carriers,
- \( E \) is the electric field strength.

### Step 3: Rearranging the Formula
From the formula, we can express mobility (\( \mu \)) as:
\[ \mu = \frac{V_d}{E} \]

### Step 4: Conclusion
The ratio of drift velocity to the electric field strength is defined as mobility. Therefore, the correct answer to the question is **mobility**.

### Final Answer
The ratio of drift velocity concerning the electric field is **mobility**.

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