The magnetic flux linkage of a coil wire increases steadily by 90 mWb in a time of 450 μ s. a) Show that the rate of change of magnetic flux linkage is 200 Wb s-1. (2 Marks) b) State the emf induced across the coil by the rate of change og magnetic flux linkage. emf = ......................... V (1 Mark) (Marks available: 3) The wing span of an Airbus A300 is 44.8 m. a) What area is swept out per second when the plane is in level flight at 250 m s-1? (2 Marks) b) If the vertical component of the Earth's magnetic field is 50 μ T, what potential difference is induced between the tips of the Airbus wings? (2 Marks) (Marks available: 4) Answer Answer outline and marking scheme for question: a) 90 mWb = 90 x 10-3 Wb, 450 μ s = 450 x 10-6 s 90 x 10-3/450 x 10-6 ( = 200 Wb s-1) (2 Marks) b) 200 V (1 Mark) (Marks available: 3) a) Area per second = wing span x speed (1 Mark) = 44.8 x 250 = 1.12 x 104 m2 s-1 (1 Mark) (2 Marks) b) Magnetic flux = B x A = 50 x 10-6 x 1.12 x 104 wb (1 Mark) emf = dΦ = 0.56 volts (1 Mark) dt (2 Marks) (Marks available: 4)