1. Two long solenoids are placed in the coaxial position, oneinside the other, they have 30 cm and 20 cm diameters,respectively. The outer solenoid is 2 m long with 5000 turns, andcarrying a current of 4 A. The inner one is 1 m long with 2000turns, and carrying a current of 2 A in the opposite sense. Findthe magnitude of the magnetic field (in mT) at any point on thesolenoid axis inside.
A. 10.52
B. 3.68
C. 15.08
D. 7.54
2.
A straight conductor is split into identical semicircular turns,as shown in the figure. What is the magnetic field at the center ofthe circular loop?
 Â
A. μoi/2R
B. μoiR/4
C. 0
D. μoi/4R
3.
Which of the followings are correct for Ampere’s Law? (Choosethree correct answers)
A. The magnetic field decreases non-linearly outside of acurrent carrying wire Â
B. The net magnetic field is zero at the both end of the currentcarrying wire Â
C. The magnetic field has its maximum value on the surface of acurrent carrying wire Â
D. The magnetic field increases linearly within a current carryingwire from its center to its surface
