Given,
Number of turns, N=200
Length of teh solenoid, l=20 cm=0.2 m
Current, I=3.25 A.
Charge is

The velocity is v=1050 m/s
Angle is

To find
a. Magnetic field inside the solenoid
b. The force
Step-by-step explanation
a. The magnetic field is

n is the number of turns per unit length.
Thus,

So,

b. The magnetic force is given by:

Conclusion
a.The magnetic field is 4.08 mT
b.The magnetic force is
