Question

A coil is placed in magnetic field such that plane of coil is perpendicular to the direction of magnetic field. The magnetic flux through a coil can be changed :
A. By changing the magnitude of the magnetic field within the coil.
B. By changing the area of coil within the magnetic field.
C. By changing the angle between the direction of magnetic field and the plane of the coil.
D. By reversing the magnetic field direction abruptly without changing its magnitude.
Choose the most appropriate answer from the options given below :

• A. A and C only
• B. A, B and C only
• C. A, B and D only
• D. A and B only

Answer 1

Answer: (B)

$\varphi =\vec{B}\cdot \vec{A}$
$=BA\cdot \cos \theta$
Most suitable ans is 2 [Otherwise ABCD]