please help me with these questions

Problem: Three nichrome wires are in series one right after the other in a circuit. Wire 1 has radius rii Wire 2 has radius r2; Wire 3 has radius ra. After the circuit reaches steady state, an ammeter measures current I in the middle section (with radius r2). If ra = 5r], what is the relationship between the drift velocities v1 and Va? O V1 = 25V3 OVI = 5Va None of the above Problem: Purdue Pete has placed a small ball of charge q = 4.0 Coulombs at the top of Purdue's Bell Tower, 51 meters above the ground. You run directly under the tower heading north at 5 m/sec, holding a very sensitive magnetometer (device to measure magnetic fields). You are holding the magnetometer so that its height is 1 m off the ground. What magnetic field do you measure due only to the ball of charge? 0 4.0x107 Tesla, directly up O Zero 0 4.0x10- Tesla, toward the South 0 8.0*10 10 Tesla, toward the East 0 8.0*10-10 Tesla, toward the WestProblem: In the circuit shown below, bulbs 1 and 2 are identical in mechanical construction (the filaments have the same length and the same cross-sectional area), but the filaments are made of different metals. The electron mobility in the metal used in bulb 2 is three times as large as the electron mobility in the metal used in bulb 1, but both metals have the same number of mobile electrons per cubic meter. The two bulbs are connected in series to two batteries with thick copper wires. In bulb 1, the electron current is in and the electric field is E1. Next when bulb 2 is replaced by a wire, the electron current through bulb 1 is in and the electric field in bulb 1 is Ep. How big is i, in terms of io ? Bulb O i1 = 10 / 2 0 1 = 10/ 3 Of1 = 310 / 4 Oh = 410/ 3 Problem: A thin circular coil of wire of radius 7 cm consists of 60 turns of wire, as shown in the figure. N turns If the conventional current in the wire is 8 amperes, what is the magnetic field at the center of the coil? The direction of conventional current is shown. Assume that the +x axis points to the right, the +y axis points up and the +2 axis points out of the page. o The magnetic field is equal to zero at the center of the coil 0 7.2 x 10" T in -z direction 0 7.2 x 10 ' T in +z direction 0 8.6 x 10"T in -z direction 0 4.3 x 10- T in +z directionProblem: A bar magnet with magnetic dipole moment (6,0,0) A . m is located at the origin. A second bar magnet with magnetic dipole moment (1,0,0) is located at (0.5,0.6,0) m. Calculate the value of u that makes the magnetic field at (0.5,0,0) m equal to zero. 0 20.7 A . m2 0 10.4 A . m2 0 17.3 A . m2 0 6.9 A . m2 0 8.6 A . m2 Problem: The emf of a particular flashlight battery is 1.5 volts. If the battery is 4.5 cm long, and the radius of the cylindrical battery is 1 cm, estimate roughly the amount of charge on the positive end plate of the battery. 0 9 x 10-14 c 0 7 x 10-2 c 0 1 x 10-20 c 0 2 x 10-2 c