Question

SI unit of displacement current is (A) coulomb (B) ampere (C) faraday (D) volt

Short answer

The SI unit of displacement current is (B) ampere.

Step-by-step solution

Recall the definition of displacement current.

Displacement current is a concept introduced by James Clerk Maxwell to explain the behavior of electric fields that change with time. It is an effective current that appears in dielectric materials when the electric field inside the material changes. Mathematically, it is defined as the rate of change of the electric displacement field (D) with respect to time.

Write the formula for displacement current.

According to the definition, the displacement current (I_D) is given by: \[ I_D = \epsilon_0 \frac{d\Phi_E}{dt} \] where \( \epsilon_0 \) = vacuum permittivity (F/m) \( \Phi_E \) = electric flux (V.m) t = time (s)

Analyze the formula and find the SI unit.

Now, let's analyze the formula: \( I_D \) is the displacement current we are looking for. \( \epsilon_0 \) is a constant and its unit is Farad per meter (F/m). \( \frac{d\Phi_E}{dt} \) is the rate of change of electric flux over time, so its unit is Volt.meters per second (V.m/s). By multiplying the units on the right-hand side of the formula, we get the unit of displacement current: \[ (F/m) \times (V.m/s) = A \] So, the SI unit of displacement current is Ampere (A).

Choose the correct answer.

Based on the previous steps, the correct answer is: (B) ampere