Govt. Exams
Induced EMF ε = -N × dΦ/dt = -100 × 0.1 = -10 V. The magnitude is 10 V.
Φ = BA cos θ. Since B is perpendicular to the surface, θ = 0° and cos θ = 1. Φ = 0.5 × 2 = 1 Wb.
From qvB = mv²/r, we get r = mv/(qB). This is the radius of curvature for a charged particle in a perpendicular magnetic field.
Magnetic force is always perpendicular to velocity, so it does no work. Kinetic energy (½mv²) remains constant, but direction changes, so velocity changes while speed remains constant.
1 Tesla = 1 Weber/m² = 1 kg/(A·s²). This is the correct dimensional formula for magnetic field intensity.
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.
