4. A squre coil of wire with 800 turns and size a = 10.0 cm on each side, is held next to a long straight wire which carries a time varying current I(t) = 9×10ª e-0.08t Amperes. Assume the center of the coil is 102.0 cm away from the wire and the coil and the wire are in the same plane. a) What is the value and direction of the B field, due to current in the straight wire, at the center of the coil (as a function of time)? b) Calculate the flux of this B-field through the coil (as a function of time). Assume the B field is uniform inside the coil, because coil is small and far from wire. c) Use the Faraday's law to determine the generated EMF (as a function of time) in the coil. d) If the resistance of the coil is R=20 Q, what is the torque acting on the coil at time t ? e) What is the potential energy of the coil at time t ? f) Answer (d) and (e), if the coil is now at an angle of 0 with respect to vertical. Coil i(t) a

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A 0.25 m long solenoid contains 104loops of wire. What current will be necessary to produce a 0.5 T magnetic field inside the solenoid?

12.0 cm X 1₁ = 9.0A I₂ = 12.0A Two long, straight, parallel wires, 12.0 cm apart, carry currents in the opposite directions as shown in the figure. Find the magnitude and direction of the magnetic field midway between the wires. 0.5 x 10-5 T, upward 0.5 x 10-5 T, downward 3.5 x 10-5 T, upward 3.5 x 10-5 T, downward 7.0 x 10-5 T, upward 7.0 x 10-5 T, downward 1.0 x 10-5 T, upward 1.0 x 10-5 T, downward O 1.2 x 10-5 T, upward 1.2 x 10-5 T, downward 8.4 x 10-5 T, upward 8.4 x 10-5 T, downward 3.0 x 10-5 T, upward 3.0 x 10-5 T, downward

6. A loop of a wire has the shape shown in the drawing. The top part of the wire is bent into a semicircle of radius r = 0.18 m. The normal to the plane of the loop is parallel to a constant magnetic field of magnitude 0.88 T. What is the magnitude of the change in the magnetic flux that passes through the loop when, starting with the position shown in the drawing, the semicircle is rotated through quarter of a revolution? Wb B (into paper) 190of19 oof19 oon9 oof 19.0of19 oof19 o 19 0of19 oof19 oo of19 oof oof19 19 0of19 0of19 oof19 oof19 o0

A circular loop of wire has an area of 0.30 m2m2 . It is tilted by 50 degrees with respect to a uniform 0.43 TT magnetic field. What is the magnetic flux through the loop? A) 8.3×10−2 T⋅m2T⋅m2 B) 0.15 T⋅m2T⋅m2 C) 0.33 T⋅m2T⋅m2 D) 0.78 T⋅m2T⋅m2 E) 1.5 T⋅m2T⋅m2