Target Exam

CUET

Subject

Physics

Chapter

Electromagnetic Waves

Question:

The conduction current is the same as displacement current when the source is:

Options:

A.C. only

D.C. only

Both A.C. and D.C.

neither for A.C. nor for D.C.

Correct Answer:

A.C. only

Explanation:

$\text{Displacement current } I_d = \epsilon_0 \frac{d\Phi_E}{dt}$

$\text{For D.C.: electric field is constant} \Rightarrow \frac{d\Phi_E}{dt} = 0$

$I_d = 0$

$\text{Conduction current } I \neq 0$

$\text{For A.C.: electric field varies with time}$

$\text{Maxwell’s equation ensures } I = I_d$

The correct answer is A.C. only.