What is the direction of a compass needle placed at point A?

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1 SAMPLE QUIZ: COVERAGE OHM S LAW CIRCUIT ANALYSIS RESISTANCE ELECTRICAL POWER MAGNETISM AND ELECTROMAGNETISM MAGNETISM: 1. In order to produce a magnetic field, an electric charge must be 1. stationary 2. moving 3. positive 4. negative 2. The diagram below shows a bar magnet. What is the direction of a compass needle placed at point A? 1. up 2. down 3. right 4. left 3. Which type of field is present near a moving electric charge? 1. an electric field, only 2. a magnetic field, only 3. both an electric field and a magnetic field

2 4. neither an electric field nor a magnetic field The diagram below shows the lines of magnetic force between two north magnetic poles At which point is the magnetic field strength greatest? 1. A 2. B 3. C 4. D 4. The diagram below shows a wire moving to the right at speed v through a uniform magnetic field that is directed into the page.

3 As the speed of the wire is increased, the induced potential difference will 1. decrease 2. increase 3. remain the same 5.. Moving a length of copper wire through a magnetic field may cause the wire to have a 1. potential difference across it 2. lower temperature 3. lower resistivity 4. higher resistance 6 The diagram below shows the magnetic field lines between two magnetic poles, A and B.

4 Which statement describes the polarity of magnetic poles A and B? 1. A is a north pole and B is a south pole. 2. A is a south pole and B is a north pole. 3. Both A and B are north poles. 4. Both A and B are south poles. 7. When two ring magnets are placed on a pencil, magnet A remains suspended above magnet B, as shown below. Which statement describes the gravitational force and the magnetic force acting on magnet A due to magnet B? 1. The gravitational force is attractive and the magnetic force is repulsive. 2. The gravitational force is repulsive and the magnetic force is attractive. 3. Both the gravitational force and the magnetic force are attractive. 4. Both the gravitational force and the magnetic force are repulsive 8. Magnetic fields are produced by particles that are 1. moving and charged 2. moving and neutral 3. stationary and charged 4. stationary and neutral 9 The diagram below represents a 0.5-kilogram bar magnet and a 0.7-kilogram

5 bar magnet with a dis- tance of 0.2 meter between their centers. Which statement best describes the forces between the bar magnets? 5. Gravitational force and magnetic force are both repulsive 6. Gravitational force is repulsive and magnetic force is attractive. 7. Gravitational force is attractive and magnetic force is repulsive. 8. Gravitational force and magnetic force are both attractive. 10 A small object is dropped through a loop of wire connected to a sensitive ammeter on the edge of a table, as shown in the diagram below. A reading on the ammeter is most likely produced when the object falling through the loop of wire is a a. flashlight battery b. bar magnet c. brass mass d. plastic ruler 11. An electron moving at constant speed produces a. a magnetic field, only b. an electric field, only c. both a magnetic and an electric field d. neither a magnetic nor an electric field Circuits-Current

6 1. The current through a lightbulb is 2.0 amperes. How many coulombs of electric charge pass through the lightbulb in one minute? C C C C 2. A 1.5-volt, AAA cell supplies 750 milliamperes of current through a flashlight bulb for 5.0 minutes, while a 1.5-volt, C cell supplies 750 milliamperes of current through the same flashlight bulb for 20 min- utes. Compared to the total charge transferred by the AAA cell through the bulb, the total charge transferred by the C cell through the bulb is 1. half as great 2. twice as great 3. the same 4. four times as great 3. A net charge of 5.0 coulombs passes a point on a con-ductor in second. The average current is A A A A 4 An ammeter (A) is connected in series to measure current in a resistor wire. What is the current in the wire if electrons pass by a point in this wire every 60 seconds? A A A A

7 4. A charge of 30 coulombs passes through a 24-ohm resistor in 6.0 seconds. What is the current through the resistor? A A A A Circuits-Resistance 1. In a simple electric circuit, a 24-ohm resistor is connected across a 6-volt battery. What is the current in the circuit? A A A A 2 The graph below represents the relationship between the current in a metallic conductor and the potential difference across the conductor at constant temperature. Remember that resistance is (voltage (V) /current (I)) where voltage is the change in potential difference. Be careful since your graph is not voltage in y vs current in x-axis BUT current in y-axis vs. potential difference (V) in the x- axis. The resistance of the conductor is Ω Ω Ω Ω

8 3 The diagram below represents a lamp, a 10-volt battery, and a length of nichrome wire connected in series. As the temperature of the nichrome is decreased, the brightness of the lamp will 1. decrease 2. increase 3. remain the same

9 4.Which graph best represents the relationship between resistance and length of a copper wire of uniform cross- sectional area at constant temperature? Remember that Resistance= Resistivity * (Length/Area) 5.Several pieces of copper wire, all having the same length but different diameters, are kept at room temperature. Which graph best represents the resistance, R, of the wires as a function of their cross-sectional areas, A? Remember that Resistance= Resistivity * (Length/Area) 6 Which quantity and unit are correctly paired? 1. resistivity and Ω/m 2. potential difference and ev 3. current and C s 4. electric field strength and N/C 7 Which changes would cause the greatest increase in the rate of flow of charge through a conducting wire? 5. increasing the applied potential difference and decreasing the length of wire 6. increasing the applied potential difference and increasing the length of wire 7. decreasing the applied potential difference and decreasing the length of wire 8. decreasing the applied potential difference and increasing the length of

10 wire 8..The electrical resistance of a metallic conductor is in- versely proportional to its 9. temperature 10. length 11. cross-sectional area 12. resistivity Circuits-Ohm's Law 1 The graph below represents the relationship between the potential difference (V) across a resistor and the current (I) through the resistor. Through which entire interval does the resistor obey Ohm s law? 1. AB 2. BC 3. CD 4. AD

11 2.A potential drop of 50 volts is measured across a 250- ohm resistor. What is the power developed in the resistor? W W W W 3..Which graph best represents the relationship between the electrical power and the current in a resistor that obeys Ohm s Law?. NOTE: To figure out the shape of the graph, you must use power equation with resistance ( R ) in it. There are three power equations. Note that the relation power = IV does not have R in it 4.Which graph best represents the relationship between the power expended by a resistor that obeys Ohm s Law and the potential difference applied to the resistor? NOTE: To figure out the shape of the graph, you must use power equation with resistance ( R ) in it. There are three power equations. Note that the relation power = IV does not have R in it. 5.The resistance of a 60-watt lightbulb operated at 120 volts is approximately? (Use one of the three power equation: Us the one with power (P), V and R in it).

12 ohms ohms ohms ohms 6..An electric iron operating at 120 volts draws 10 amperes of current. How much heat energy is delivered by the iron in 30 seconds? (Remember that power = IV and Energy or Work = Power * time) or Power = Work /time) J J J J 7..How much total energy is dissipated in 10 seconds in a 4-ohm resistor with a current of 0.50 ampere? ( Hint: Remember that Energy or Work = Power * Time and Power dissipated (power lost as heat in a wire) is given by Joule s Law i.e. ( square of current)*(resistance) J J J J 8..Which physical quantity is correctly paired with its unit? 1. power and watt seconds 2. energy and newton seconds 3. electric current and amperes/coulomb 4. electrical potential difference and joules/coulomb

13 9.. The total amount of electrical energy used by a 315- watt television during 30.0 minutes of operation is? { Hint: Energy or Work = Power in watt * time in seconds J J J J Circuits-Circuit Analysis

14 1.A 9-volt battery is connected to a 4-ohm resistor and a 5-ohm resistor as shown in the diagram below. What is the current in the 5-ohm resistor? A A A A 2 In which circuit would current flow through resistor R1 but not through resistor R2 while switch S is open? Which circuit diagram below correctly shows the connection of ammeter A and voltmeter V to measure the current through and potential difference across resistor R?

15 3 In which circuit would an ammeter show the greatest total current? 4 As the number of resistors in a parallel circuit is increased, what happens to the equivalent resistance of the circuit and total current in the circuit? 1.Both equivalent resistance and total current decrease. 2. Both equivalent resistance and total current increase. 3. Equivalent resistance decreases and total current increases. 4. Equivalent resistance increases and total current decreases.

16 Base your answers to questions 28 and 29 on the circuit diagram below. 5. If switch S1 is open, the reading of ammeter A is A A A A 6. If switch S1 is closed, the equivalent resistance of the circuit is 1. 8 ohms 2. 2 ohms 3. 3 ohms ohms 7.. The diagram below shows a circuit with two resis- tors. 8 What is the reading on ammeter A? A A A A 9..What must be inserted between points A and B to establish a steady electric current in the incomplete circuit represented in the diagram below?

17 1. switch 2. voltmeter 3. magnetic field source 4. source of potential difference 10.The diagram below represents a simple circuit con- sisting of a variable resistor, a battery, an ammeter, and a voltmeter What is the effect of increasing the resistance of the variable resistor from 1000 Ω to Ω? [Assume constant temperature.] 5. The ammeter reading decreases. 6. The ammeter reading increases. 7. The voltmeter reading decreases. 8. The voltmeter reading increases The diagram below shows currents in a segment of an electric circuit.

18 12..What is the reading of ammeter A? (Hint : Current going in a junction must be equal to current going out of a junction or a point in a circuit: Current law state that TOTAL CURRENT IN = TOTAL CURRENT OUT ) 1. 1 A 2. 5 A 3. 9 A A 13..Magnetism and Electromagnetism: Nicola Tesla preferred AC current to DC current while Thomas Edison Preferred DC to AC Current. True False