Question

The magnetic flux through a loop placed in a magnetic field can be changed by changing:

• A. area of the loop only
• B. the value of magnetic field only
• C. orientation of the loop in the magnetic field only
• D. any one or more of the factors given in (A), (B) and (C)

Hint:

Remember the flux formula \( \Phi = BA\cos\theta \): If any of \( B \), \( A \), or \( \theta \) changes, magnetic flux changes.

Answer 1

The Correct Option is D

Concept: Magnetic flux through a loop is given by: \[ \Phi = B A \cos\theta \] Where:

\( B \) = magnetic field strength
\( A \) = area of the loop
\( \theta \) = angle between magnetic field and area vector

Step 1: Changing area. If the area \( A \) changes, flux changes since: \[ \Phi \propto A \]
Step 2: Changing magnetic field. If the magnetic field strength changes: \[ \Phi \propto B \] So flux changes.
Step 3: Changing orientation. If the loop is rotated, angle \( \theta \) changes. Since: \[ \Phi \propto \cos\theta \] Flux also changes.
Step 4: Conclusion. Magnetic flux depends on all three factors:

Area
Magnetic field
Orientation
Changing any one (or more) of them changes flux.