TALLER DE ELECTRICIDAD Y MAGNETISMO 9º

Transcription

1 TALLER DE ELECTRICIDAD Y MAGNETISMO 9º MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) Compared to the resistance of two resistors connected in series, the same two resistors connected in parallel have A) less resistance. B) more resistance. C) the same resistance. 1) 2) As more lamps are put into a parallel circuit, the overall current in the power source 2) A) increases. B) stays the same. C) decreases. 3) As more lamps are put into a series circuit, the overall current in the power source 3) A) decreases. B) increases. C) stays the same. 4) A 4-ohm resistor is connected in parallel with a 6-ohm resistor. This combination produces an equivalent resistance of A) 10 ohms. B) 2.4 ohms. C) 5 ohms. D) 5.5 ohms. E) 4 ohms. 4) 5) When two 1-ohm resistors are connected in series, their combined resistance is 5) A) 1 ohm, and when connected in parallel, 2 ohms. B) 2 ohms, and when in parallel, 1 ohm. C) 2 ohms, and when in parallel, 1/2 ohm. D) 1/2 ohm, and when in parallel, 2 ohms. Figura ) Tres focos A,B y C, tienen las especificaciones eléctricas siguientes: Foco A - 97 W, 2.7 A Foco B - 80 V, 205 W Foco C V, 0.1 A Los tres focos se conectan en un circuito, alimentado a través de una línea de 150 V, como se muestra. Considerar que las resistencias de los filamentos en los focos son constantes e independientes de las condiciones de operación. En la Figura 26.1, la resistencia equivalente del circuito corresponde a: 6) A) 53 B) 35 C) 44 D) 61 E) 70

2 SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question. 7) Draw a circuit with a battery connected to four resistors, R1, R2, R3, and R4, as follows. Resistors R1 and R2 are connected in parallel with each other, resistors R3 and R4 are connected in parallel with each other, and both parallel sets of resistors are connected in series with each other across the battery. 7)

3 MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 8) Identical light bulbs can be attached to identical ideal batteries in three different ways (A, B, or C), as shown in the figure. The ranking (from lowest to highest) of the total power produced by the battery is 8) A) C, A, B B) B, A, C C) C, B, A D) A, B, C E) A, C, B 9) Identical ideal batteries are connected in different arrangements to the same light bulb, as shown in the figure. For which arrangement will the bulb shine the brightest? 9) A) A B) B C) C SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question. 10) What is the equivalent resistance between points A and B of the network shown in the figure? 10)

4 MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 11) A combination of a 2.0- resistor in series with 4.0- resistor is connected in parallel with a 3.0- resistor. What is the equivalent resistance of this system? A) 3.0 B) 4.0 C) 9.0 D) ) 12) What is the equivalent resistance in the circuit shown in the figure? 12) A) 80 B) 35 C) 55 D) 50 13) The source of all magnetism is 13) A) tiny domains of aligned atoms. B) moving electric charge. C) tiny pieces of iron. D) ferromagnetic materials. 14) Magnetic compasses apparently were first used by 14) A) Australian aborigines. B) Vikings. C) pigeons, then Chinese. D) Greeks. E) Columbus. 15) Magnetic domains normally occur in 15) A) copper. B) iron. C) silver. D) all of these 16) The intensity of cosmic rays bombarding the Earth's surface is largest at the 16) A) equator. B) mid-latitudes. C) poles. 17) Which pole of a compass needle points to a south pole of a magnet? 17) A) north pole B) south pole C) both of these

5 18) What is the explanation of Earth's magnetism? 18) A) Earth's magnetism a consequence of the world's physics professors all spinning in the same direction. B) It is caused by charged, or ionized, particles circulating in the air above the solid Earth. C) It is caused by a separation of charge within the Earth, with positive static charge residing at one of Earth's poles and negative static charge residing at the other pole. D) It is caused by electrically charged material circulating within Earth's hot liquid core. E) Subatomic particles known as "magnetic poles" reside in the Earth, with one type of magnetic pole residing at Earth's north pole and the other type of magnetic pole residing at Earth's south pole. 19) The figure below shows 3 bar magnets of equal sizes and equal strengths. At which of the points labeled A to E is the magnetic field approximately equal to zero? (Points B and C are at equal distances from the magnets.) 19) A) A B) B C) C D) D E) E SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question. 20) The unit of magnetic field strength is known as the. 20)