Question

Biot--Savart's law is most suitable for calculating magnetic field due to

• A. Infinitely long straight conductor
• B. Symmetrical current distributions only
• C. Small current elements
• D. Changing electric fields

Hint:

\[ \boxed{ \text{Biot--Savart law} \rightarrow \text{Magnetic field due to a current element }(I\,d\ell) } \] Ampere's law is generally preferred for highly symmetric current distributions.

Answer 1

The Correct Option is C

Step 1: Recall Biot--Savart's law. Biot--Savart's law gives the magnetic field produced by an infinitesimal current element \(I\,d\ell\). \[ dB=\frac{\mu_0}{4\pi} \frac{I\,d\ell\sin\theta}{r^2}. \]

Step 2: Identify the correct option. The law is primarily used to determine the magnetic field due to \[ \boxed{\text{small current elements}.} \] Therefore, \[ \boxed{(C)} \] is the correct answer.