Magnetic Flux - Practice Questions & MCQ

A magnetizing field of produces a magnetic flux of in an iron bar of cross-sectional area . The susceptibility of an iron bar is.

A person wants to roll a solid non-conducting spherical ball of mass m and radius r on a surface whose coefficient of static friction is . He placed the ball on the surface wrapped with n turns of closely packed conducting coils of negligible mass at the diameter. By some arrangement he is able to pass a current i through the coils either in the clockwise direction or in the anti-clockwise direction.

A constant horizontal magnetic field B is present throughout the space as shown in the figure. (Assume is large enough to help rolling motion)

Question

If current i is passed through the coils the maximum torque in the coil is

Write–Up–II
A person wants to roll a solid non-conducting spherical ball of mass m and radius r on a surface whose coefficient of static friction is . He placed the ball on the surface wrapped with n turns of closely packed conducting coils of negligible mass at the diameter. By some arrangement he is able to pass a current i through the coils either in the clockwise direction or in the anti-clockwise direction.

A constant horizontal magnetic field B is present throughout the space as shown in the figure. (Assume  is large enough to help rolling motion)

Question

Angular acceleration of the ball after it has rotated through an angle , is

Write–Up–II
A person wants to roll a solid non-conducting spherical ball of mass m and radius r on a surface whose coefficient of static friction is . He placed the ball on the surface wrapped with n turns of closely packed conducting coils of negligible mass at the diameter. By some arrangement he is able to pass a current i through the coils either in the clockwise direction or in the anti-clockwise direction.

A constant horizontal magnetic field B is present throughout the space as shown in the figure. (Assume  is large enough to help rolling motion)

Question

The minimum value of  for which the rolling motion is possible, is