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A strong electromagnet produces a uniform magnetic eld of 1.60 T over a cross-sectional area of 0.320 m2. A coil having 240 turns and a total resistance of 19.0 n is placed around the electromagnet. The current in the electromagnet is then smoothly reduced until it reaches zero in 20.0 ms. What is the current induced in the coil? :A A 23-turn circular coil of radius 3.60 cm and resistance 1.00 0 is placed in a magnetic Field directed perpendicular to the plane of the coil. The magnitude of the magnetic field varies in time according to the expression 3 = 0.010 Ot + 0.040 0t2, where B is in teslas and t is in seconds. Calculate the induced emf in the coil at t = 5.20 5. SW The figure below shows a top View of a bar that can slide on two frictionless rails. The resistor is R = 6.80 D, and a 2.50-T magnetic field is directed perpendicularly downward, into the page. Let 1'? = 1.20 m. XXXXXX _xxxxxx (a) Calculate the applied force required to move the bar to the right at a constant speed of 1.50 m/s. N (to the right) (b) At what rate is energy delivered to the resistor? :W Within the green dashed circle shown in the figure below, the magnetic field changes with time according to the expression B = 9.00t - 1.00t + 0.800, where B is in teslas, t is in seconds, and R = 3.00 cm. P R x Bin (a) When t = 2.00 s, calculate the magnitude of the force exerted on an electron located at point P, which is at a distance r, = 6.00 cm from the center of the circular field region. N (b) When t = 2.00 s, calculate the direction of the force exerted on an electron located at point P , which is at a distance r, = 6.00 cm from the center of the circular field region. O tangent to the electric field line passing through point P, and clockwise O tangent to the electric field line passing through point P, and counterclockwise O The magnitude is zero. (c) At what instant is this force equal to zero? (Consider the time after t = 0 s.)In a 270-turn automobile a ternator, the magnetic Flux in each turn is (DB = 2.50 x 10'4 cos mt, where CDB is in webers, (u is the angular speed of the alternator, and t is in seconds. The alternator is geared to rotate six times for each engine revolution. The engine is running at an angular speed of 1.00 x103 rev/min. (a) Determine the induced emf in the alternator as a function of time. (Assume 8 is in V.) 8: (b) Determine the maximum emf in the alternator: |:|V The circuit in the figure below is located in a magnetic field whose magnitude varies with time according to the expression B = 1.00 x 10" t, where B is in teslas and t is in seconds. Assume the resistance per length of the wire is 0.103 0/m. Find the current in section PQ of length a = 67.0 cm. magnitude HA direction ---Select--- :.......: P X X X X X X X X X X X 2a Q a