1 A 120-W lightbulb is placed across a generator with I max of 0.650 A. If the maximum voltage of the generator is 150.0 V, what is the resistance of the bulb?A) 116 Ω B) 163 Ω C) 326 Ω D) 231 Ω 2 In the figure below, if the wire were moved to the left instead of the right, what would the direction of the magnetic force on it be?
(7.0K)A) into the page B) down C) up D) out of the page 3 A 0.30-m long straight wire moves at a constant speed of 9.5 m/s perpendicular to a magnetic field of strength 0.083 T. What EMF is induced in the wire?A) 0.48 V B) 1.2 V C) 2.6 V D) 0.24 V 4 A wire 15 m long moves through a magentic field of 1.0 T. The wire moves at a constant speed of 5.7 m/s in a direction perpendicular to the magnetic field. What EMF is induced in the wire?A) 2.6 V B) 86 V C) 43 V D) 61 V 5 Electromotive force is the same as __________.A) magnetic flux B) current C) resistance D) potential difference 6 A changing magnetic field can produce a(n)__________.A) electric current B) resistor C) spark of electricity D) force 7 What is the unit for EMF ?A) C/J B) V C) N D) N m 8 In the figure below, if the north and south poles were switched, what would the direction of the magnetic force on the wire be?
(7.0K)A) up B) out of the page C) down D) into the page 9 If the average power dissipated by an electric light is 75 W, what is the maximum power?A) 150 W B) 100 W C) 50 W D) 75 W 10 You want to generate an EMF of 2.6 V by moving a wire at 3.0 m/s through a 0.040-T magnetic field. If you keep the wire perpendicular to the magnetic field, what length of wire should you use?A) 22 m B) 0.035 m C) 0.046 m D) 11 m 11 An AC generator produces a maximum voltage of 512 V and a maximum current of 0.80 A. What is the effective voltage and effective current of the generator?A) 362 V, 0.57 A B) 362 V, 1.13 A C) 362 V, 1.13 A D) 362 V, 1.13 A 12 Effective voltage is equal to 0.707 times the maximum voltage. Effective current is equal to 0.707 time the maximum current.A) to the right B) toward you C) downward D) upward 13 __________ is the generation of current due to relative motion between a wire and a magnetic field.A) Magnetic flux B) Electromagnetic induction C) Electrolysis D) Electrospectrometry 14 An electric generator converts __________.A) mechanical energy into electrical energy B) electrical energy into magnetic energy C) magnetic energy into electrical energy D) magnetic energy into electrical energy 15 What does EMF not depend upon?A) velocity of wire B) velocity of wire C) velocity of wire D) length of wire 16 Effective current and voltage relate to __________.A) average resistance B) equivalent resistance C) alternating current D) magnetic fields 17 A current __________ in a stationary wire in an unchanging magnetic field.A) is not produced B) is easily generated C) always exists D) cannot exist 18 A transformer goes from 10 V to 5000 V. How do the number of loops relate in the different coils?A) There are 500 times more loops in the primary coil. B) There are 500 times more loops in the secondary coil. C) There are 5000 times more loops in the primary coil. D) There are 50 times more loops in the secondary coil. 19 A step-down transformer has 80,000 turns on its primary coil and 500 turns on its secondary coil. If the primary coil is attached to a generator with an EMF of 45.0 V, what is the EMF in the secondary coil?A) 1.39×10-4 V B) 3.56 V C) 0.281 V D) 7.20×103 V 20 In the figure below, if the primary coil were increased to 10 turns while its voltage and current were kept the same, what effect would this have on the secondary coil?
(8.0K)A) Its number of turns would increase. B) Its power would increase. C) Its voltage would decrease. D) Its current would decrease. 21 A transformer is a device to increase or decrease AC __________.A) power B) heat C) voltage D) resistance 22 In a transformer, the primary coil has twice as many loops as the secondary coil. This is a __________ transformer.A) step-down B) step-up C) reduction D) voltage 23 What happens to the secondary current in a step-up transformer?A) It is not affected. B) It remains the same. C) It increases. D) It decreases. 24 Electricity sent over power lines needs __________.A) low voltage and high current B) low voltage and low current C) high voltage and low current D) high voltage and high current 25 A step-up transformer has 400 turns on its primary coil and 1000 turns on its secondary coil. If the secondary coil has a current of 1.30 A, what is the current in the primary coil?A) 0.520 A B) 3.25 A C) 7.75 A D) 1.62 A 26 __________ is (are) generated when a piece of metal moves through a magnetic field.A) Eddy currents B) Lenz's laws C) Voltage drop D) EMF 27 In the figure below, if the primary coil's current were increased while its voltage was kept the same, what effect would this have on the secondary coil?
(8.0K)A) Its power would decrease. B) Its number of turns would increase. C) Its voltage would decrease. D) Its current would increase. 28 According to Lenz's law, the resulting force produced by an induced current __________.A) reduces the resistance B) opposes the motion of the wire C) contributes to the motion of the wire D) opposes the current 29 A carpenter turns on the power to a table saw in his workshop. The lights dim and return to full brightness after the motor is going at full speed. Why does this occur?A) back-EMF of the motor B) a short reduction in voltage due to the power company C) a short circuit D) back-EMF of the light 30 In the figure below, if the primary coil's voltage were increased while the current were kept the same, what effect would this have on the secondary coil?
(8.0K)A) Its current would decrease. B) Its voltage would increase. C) Its number of turns would increase. D) Its power would decrease.