Exam #3: Physics Magnetism I a) 2R b) R c) R/2 d) 4R e) R/4 2) Inside a solenoid, the magnetic field, 'a) Is zero b) decreases along the axis b) Increases along the axis d) Is uniform 3) A proton enters a magnetic field of 10T and an electric field of 2000 N/Cin such a way that it passes both fields undeflected. The velocity of the proton is; a) 2000 b) 200 c) 200,000 d) 20,000 4) Which of the following will decreases the strength of the magnetic field of a solenoid? a) Increases the permeability of the core b) Increase the temperature of the solenoid c) Increase the current d) Increase the number of turns of wire