Answer:
Magnetic field,

Step-by-step explanation:
It is given that,
Number of turns, N = 320
Radius of the coil, r = 6 cm = 0.06 m
The distance from the center of one coil to the electron beam is 3 cm, x = 3 cm = 0.03 m
Current flowing through the coils, I = 0.5 A
We need to find the magnitude of the magnetic field at a location on the axis of the coils, midway between the coils. The magnetic field midway between the coils is given by :


B = 0.00239 T
or

So, the magnitude of the magnetic field at a location on the axis of the coils, midway between the coils is
. Hence, this is the required solution.