A magnetic needle is kept in a non-uniform magnetic field. It experiences
Correct answer: A. A force and a torque
- A. A force and a torque
- B. A force but not a torque
- C. A torque but not a force
- D. Neither a torque nor a force
Explanation
A magnetic needle placed in a non-uniform magnetic field experiences both a force and a torque. The non-uniform field exerts a force on the needle due to the field's gradient, which can move the needle through space. Additionally, the field exerts a torque on the needle, which tends to align the needle with the field lines. This is because a magnetic needle behaves like a magnetic dipole, and in a non-uniform field, the forces on the north and south poles of the dipole are unequal, causing both a linear force and a rotational effect. Option B is incorrect because a torque is also experienced due to the magnetic field's non-uniformity. Option C is incorrect because the force is present as well. Option D is incorrect because both a force and a torque are exerted on the needle.
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