Ch.210.4 Flashcards
- A circular coil consists of 5 loops each of diameter 1.0 m. The coil is placed in an external magnetic
field of 0.5 T. When the coil carries a current of 4.0 A, a torque of magnitude 3.93 N-m acts on it.
Determine the angle between the normal to the plane of the coil and the direction of the magnetic field.
A) 0° B)----- 30° C) 45° D) 60° E) 90°
- A single circular loop of radius 1.00 m carries a current of 10.0 mA. It is placed in a uniform
magnetic field of magnitude 0.500 T that is directed parallel to the plane of the loop as suggested in the
figure. What is the magnitude of the torque exerted on the loop by the magnetic field?
A) ----- 1.57 × 10–2 N × m B) 3.14 × 10–2 N × m C) 6.28 × 10–2 N × m D) 9.28 × 10–2 N × m E) zero N × m
- A rectangular loop has sides of length 0.06 m and 0.08 m. The wire carries a current of 10 A in the
direction shown. The loop is in a uniform magnetic field of magnitude 0.2 T and directed in the positive x
direction. What is the magnitude of the torque on the loop?
A) 2 × 10–2 N × m B) 4 × 10–2 N × m C) 5 × 10–3 N × m D) ----- 8 × 10–3 N × m E) 1 × 10–4 N × m
- A single circular loop of wire of radius 0.45 m carries a constant current of 2.4 A. The loop may be
rotated about an axis that passes through the center and lies in the plane of the loop. When the orientation
of the normal to the loop with respect to the direction of the magnetic field is 36°, the torque on the coil is
1.5 N × m. What is the magnitude of the uniform magnetic field exerting this torque on the loop?
A) 0.37 T B) ----- 1.7 T C) 3.0 T D) 0.46 T E) 0.80 T
- A coil consists of 240 circular loops, each of radius 0.044 m, and carries a current of 2.2 A.
Determine the magnetic moment of the coil.
A) 0.21 A × m2 B) 0.65 A × m2 C) ----- 3.2 A × m2 D) 15 A × m2 E) 23 A × m2
- Which one of the following statements concerning the magnetic field inside (far from the surface) a
long, current-carrying solenoid is true?
A) The magnetic field is zero.
B) —– The magnetic field is non-zero and nearly uniform.
C) The magnetic field is independent of the number of windings.
D) The magnetic field is independent of the current in the solenoid.
E) The magnetic field varies as 1/r as measured from the solenoid axis.
- Complete the following statement: The magnetic field around a current-carrying, circular loop is
most like that of
A) the earth.
B) —– a short bar magnet.
C) a current-carrying, rectangular loop.
D) a long straight wire that carries a current.
E) two long straight wires that carry currents in opposite directions.
- A solenoid of length 0.250 m and radius 0.0250 m is comprised of 440 turns of wire. Determine the
magnitude of the magnetic field at the center of the solenoid when it carries a current of 12.0 A.
A) ----- 2.21 × 10–3 T B) 4.52 × 10–3 T C) 9.05 × 10–3 T D) 7.50 × 10–3 T E) zero tesla
- The drawing shows two long, thin wires that carry currents in the positive z direction. Both wires are
parallel to the z axis. The 50-A wire is in the x-z plane and is 5 m from the z axis. The 40-A wire is in the
y-z plane and is 4 m from the z axis. What is the magnitude of the magnetic field at the origin?
A) zero tesla B) 1 × 10–6 T C) ----- 3 × 10–6 T D) 4 × 10–6 T E) 6 × 10–6 T
- The radius of a coil of wire with N turns is r = 0.28 m. A clockwise current of I
coil = 1.0 A flows in
the coil, as shown. A long, straight wire carrying a current Iwire = 29 A toward the left is located 0.04 m
from the edge of the coil. The magnetic field at the center of the coil is zero tesla. Determine N, the
number of turns.
A) ----- 8 B) 2 C) 6 D) 4 E) 1
