16. A coil of wire is placed in a changing magnetic field. If the number of turns in the coil is decreased, the voltage induced across the coil will ________.
(a) increase
(b) decrease
(c) remain constant
(d) be excessive
17. What is the magnetomotive force (mmf) of a wire with 8 turns carrying three amperes of current?
(a) 2,400 At
(b) 240 At
(c) 24 At
(d) 2.4 At
18. What is the flux density when the flux is 5.5 μWb and the cross-sectional area is 6 × 10–3 m2?
(a) 91.7 μT
(b) 917 μT
(c) 91 T
(d) 9.7 T
19. What is the reluctance of a material that has a length of 0.07 m, a cross-sectional area of 0.014 m2, and a permeability of 4,500 μWb/At × m?
(a) 1111 At/Wb
(b) 111 At/Wb
(c) 11 At/Wb
(d) 1 At/Wb
20. When a solenoid is activated, the force that moves the plunger is ________.
(a) an electromagnetic field
(b) a permanent magnetic field
(c) varying voltage
(d) a steady current
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5555555555 2. When the speed at which a conductor is moved through a magnetic field is increased, the induced voltage ________. (a) increases (b) decreases (c) remains constant (d) reaches zero- 5555555555 5. If the cross-sectional area of a magnetic field increases, but the flux remains the same, the flux density ________. (a) increases (b) decreases (c) remains the same (d) doubles
- 5555555555 16. A coil of wire is placed in a changing magnetic field. If the number of turns in the coil is decreased, the voltage induced across the coil will ________. (a) increase (b) decrease (c) remain constant (d) be excessive
- 5555555555 20. When a solenoid is activated, the force that moves the plunger is ________. (a) an electromagnetic field (b) a permanent magnetic field (c) varying voltage (d) a steady current
- 5555555555 10. There is 900 mA of current through a wire with 40 turns. What is the reluctance of the circuit if the flux is 400 μWb? (a) 14,400 At/Wb (b) 1,440 At/Wb (c) 9,000 At/Wb (d) 90,000 At/Wb