Solution Since the coil is tightly wound, we may take each circular
element to have the same radius R = 10 cm = 0 1 m The number of
turns N = 100 The magnitude of the magnetic field is,
–7
2
0
–1
4
10
10
1
2
2
10
NI
B
µR
π ×
×
×
=
=
×
4
2
10−
=
π ×
4
6 28
10
T