Determine the magnitude of the force on the wire due to the magnetic field. You may assume the field is uniform.
current in wire = 820 mA
length of wire in field = 6.9 cm
magnetic flux density = 0.074 T
Magnitude of force = ......................
Either
Use of Pythagoras to find length of wire perpendicular to field [6.1 cm]
Use of F = B×I×length of wire perpendicular to field using
F = 0.0037 N
Or
Use of cosθ = a/h Or use of sinθ = o/h
Or measures an angle from diagram as 73°± 1°
Or measures an angle from diagram as 17°± 1°
Use of F = BIlsinθ using correct angle
F = 0.0037 N (accept F = 0.0040 N if measured angle of 73° used)
Example of calculation
cos θ = 3.2 cm / 6.9 cm
θ = 62.4°
F = 0.074 T × 0.82 A × 0.069 m × sin 62.4°
= 0.074 T × 0.82 A × 0.069 m × 0.89
F = 0.0037 N
Using measured angle:
θ = 73°
F = 0.074 T × 0.82 A × 0.069 m × sin 73°
= 0.074 T × 0.82 A × 0.069 m × 0.96
F = 0.0040 N
