Class 12 Physics Electromagnetic Induction Magnetic Flux

Magnetic Flux

• Magnetic flux is defined as the product of the average magnetic field times the perpendicular area it penetrates.
• In case of magnetic flux orientation of the area vector is considered.
• Area vector is considered as the amount of lines crossing an area also varies with the orientation of the area.
• It is a scalar quantity.
• Magnetic flux is denoted by ΦB or Φ.
• I Unit- Weber (Wb).
• Where 1Wb= 1Tesla x 1m2 (S.I. unit of B = Tesla and Area=m2)
• G.S unit-Maxwell (Mx).Relationship between Weber and Maxwell is;1Wb=108Mx
• Mathematically:
• ΦB = A
• B=magnetic field vector, A= area vector
• Area vector =In case of magnetic flux the amount of lines crossing an area varies with the orientation of the area.
• ΦB = BA cos θ
• Where θ=angle between magnetic field and area vector.
• Direction of area vector is determined by the normal to the area vector.

Case 1: When the angle between the area vector and the magnetic field (θ)= 900.

• Therefore, ΦB = 0 as cos900 =0. Case 2: When the angle between the area vector and the magnetic field (θ)= 00.

• Therefore,ΦB = BA as cos 0=1.  .