Q. An infinite line of charge has linear charge density 5.50 x10-12 C/m. A proton (mass 1.67 10-27 kg, charge +1.60 10-19 C) is 18.0 cm from the line and moving directly toward the line at 1.20 x10^3 m/s. How close does the proton get to the line of charge?
Q. A 800-turn solenoid, 21 cm long, has a diameter of 2.1 cm. A 10-turn coil is wound tightly around the center of the solenoid.If the current in the solenoid increases uniformly from 0 to 3.7 A in 0.22 s, what will be the induced emf in the short coil during this time?