QUESTION 1: A 16 cm long solenoid has 4100 turns of wire. Inside this solenoid i
ID: 1397025 • Letter: Q
Question
QUESTION 1:
A 16 cm long solenoid has 4100 turns of wire. Inside this solenoid is a second one, also 16 cmlong but with 2000 turns of wire.
A)If a 2.5 A current flows in each solenoid in the same direction, what is the magnitude of magnetic field inside the inner solenoid?
B)What’s the magnitude of magnetic field in the space between the two solenoids?
C)What is the magnitude of magnetic field inside the inner solenoid if the two carry 2.5 A currents in opposite directions?
D)What’s the magnitude of magnetic field in the space between the two solenoids?
QUESTION 2:A simple electric motor consists of a 100-turn coil 2.3 cm in diameter, mounted between the poles of a magnet that produces a 0.18 T magnetic field. When a 4.8 A current flows in the coil, what are (a) its magnetic dipole moment and (b) the maximum torque developed by the motor?
PART A]When a 4.8 A current flows in the coil, what is its magnetic dipole moment?
PART B]When a 4.8 A current flows in the coil, what is the maximum torque developed by the motor?
Explanation / Answer
A 16 cm long solenoid has 4100 turns of wire. Inside this solenoid is a second one, also 16 cmlong but with 2000 turns of wire
A)
For outer solenoid :
N = number of turns = 4100
L = length of the solenoid = 16 cm = 0.16 m
no = number of turns per unit length = N/L = 4100 / 0.16 = 25625
io = current = 2.5 A
For inner solenoid :
N = number of turns = 2000
L = length of the solenoid = 16 cm = 0.16 m
ni = number of turns per unit length = N/L = 2000 / 0.16 = 12500
ii = current = 2.5 A
magnetic field by a solenoid is given as :
B = uo ni
Total magnetic field is given as :
Btotal = Binner + Bouter
Btotal = uo niii + uo no io
Btotal = (12.56 x 10-7) (12500 + 25625) (2.5)
Btotal = 0.1197 T
B)
between the solenoids , magnetic field is due to outer solenoid , so
B = uo no io
B = (12.56 x 10-7) (25625) (2.5)
B = 0.0805 T
C)
Total magnetic field is given as :
Btotal = Bouter - Binner
Btotal = - uo niii + uo no io
Btotal = (12.56 x 10-7) (-12500 + 25625) (2.5)
Btotal = 0.0412 T
D)
between the solenoids , magnetic field is due to outer solenoid , so
B = uo no io
B = (12.56 x 10-7) (25625) (2.5)
B = 0.0805 T