Govt. Exams
Entrance Exams
Force F = BIL sin θ is maximum when sin θ = 1, which occurs at θ = 90°. This means the wire must be perpendicular to the magnetic field direction.
Magnetic force is given by F = q(v × B), which is the cross product of velocity and field. Cross product is always perpendicular to both vectors.
The magnetic field inside a solenoid is uniform and given by B = μ₀nI, where n = N/L is the number of turns per unit length. This is independent of the cross-sectional area A.
Magnetic flux density (B) is measured in Tesla (T) in SI units. 1 Tesla = 1 Weber/m². Gauss is CGS unit, Weber is unit of flux, and Henry is unit of inductance.
When a bar magnet is cut along its length, each half has half the number of magnetic dipoles. Since magnetic moment is the sum of individual dipole moments, each half has magnetic moment M/2.
Using Biot-Savart law, the magnetic field at the center of a circular loop of radius R carrying current I is B = μ₀I/2R. This is a fundamental formula in magnetism.
When a charged particle moves perpendicular to a uniform magnetic field, the magnetic force is always perpendicular to velocity, so it does no work. Hence kinetic energy remains constant. However, direction changes continuously.
