Answer all please

1. The electric field produces a potential difference. If you place one electrode 20 m below the surface of the water, the greatest potential would be measured if the second electrode is placed: 2. A circular loop of wire has an area of 0.30 m'. It is tilted by 450 with respect to a uniform 0.40 T magnetic field. What is the magnetic flux through the loop? 3. The magnetic field of the brain has been measured to be approximately 3.0 pT. Even though complicated, the currents that cause the field can be obtained by modeling them as a single circular current loop 16 cm (width of an average head) in diameter. What current is needed to produce such a field at the center of the loop? #4. An un-magnetized metal sphere hangs by a thread. When the north pole of a bar magnet is brought near the sphere, it is strongly attracted to the magnet. Then the magnet is reversed, and its south pole is brought near the sphere. How does the sphere respond? 5. A transformer has 1000 turns in the primary coil and 100 turns in the secondary coil. If the primary coil is connected to a 240 V outlet and draws 0.050 A, what are the voltage and the current of the secondary coil? 6. A flat circular coil with 40 loops of wire has a diameter of 32 cm. what current must flow in its wires to produce a field of 3.0 x 10"#Wb/m at its center? *7. A solenoid 30 cm long is made by winding 2000 loops of wire on an iron whose cross sectional area is 1.5 cm . if the relative permeability of the iron is 600, what is the self-inductance of the solenoid? What average emf is induced in the solenoid as the current in it is decreased from 0.60 A to 0.10 A in a time of 0.30 s? jona sH Of x o0 (shoes 8. In a purely inductive AC, L =25.0 mH and the rms voltage is 1.50 x102 V. Find the inductive reactance if the frequency is 60.0 Hz. 9. A certain solenoid consists of 100 turns of wire and has a length of 10.0 cm. Find the magnitude of the magnetic field inside the solenoid when it carries a current of 0.500 A