Question

A bismuth needle, when free to rotate in a strong magnetic field, shall set itself at an angle with the
field which is equal to
(A) 30°
(B) 60°
(C) 90°
(D) 120°​

Answer 1

Answer:

90 degree

Explanation:

bismuth being a diamagnetic substance it align itself perpendicular to the external magnetic field

Answer 2

A bismuth needle, when free to rotate in a strong magnetic field, shall set itself at an angle with the  field which is equal to (C) 90°

Explanation:

• Bismuth needle is a diamagnetic material which sets itself at perpendicular to the magnetic field.
• When magnetic field is applied to the material, then the magnetic field is produced in the opposite direction to the applied field. This causes repulsive force on the bismuth needle and it arranges itself towards the weakest field.
• There is no atomic dipoles in the diamagnetic material.