· web viewtwo tiny beads are 25 cm apart with no other charges or fields present. bead a carries...

CP Physic Final Exam Review1. If two objects are electrically attracted to each other,

a. both objects must be negatively charged.b. both objects must be positively charged.c. one object is negatively charged and the other object is positively charged.d. the objects could be electrically neutral.e. None of the above statements are absolutely true.

2. A plastic rod is charged up by rubbing a wool cloth, and brought to an initially neutral metallic sphere that is insulated from ground. The sphere is

a. is repelled by the rod.b. is attracted to the rod.c. feels no force due to the rod.

3. A plastic rod is charged up by rubbing a wool cloth, and brought to an initially neutral metallic sphere that is insulated from ground. It is allowed to touch the sphere for a few seconds, and then is separated from the sphere by a small distance. After the rod is separated, the sphere

a. is repelled by the rod.b. is attracted to the rod.c. feels no force due to the rod.

4. Two tiny beads are 25 cm apart with no other charges or fields present. Bead A carries 10 μC of charge and bead B carries 1 μC. Which one of the following statements is true about the magnitudes of the electric forces on these beads?

a. The force on A is 10 times the force on B.b. The force on B is 10 times the force on A.c. The force on A is exactly equal to the force on B.d. The force on A is 100 times the force on B.e. The force on B is 100 times the force on A.

5. Two point charges, Q1 and Q2, are separated by a distance R. If the magnitudes of both charges are doubled, what happens to the electrical force that each charge exerts on the other one?

a. It increases by a factor of 2.b. It increases by a factor of 4.c. It is reduced by a factor of 8.d. It increases by a factor of 16.e. It remains the same.

6. Which one of the arrows shown in the figure best represents the direction of the electric field between the two uniformly charged metal plates?

a. Ab. Bc. Cd. De. None of the above

7. A hydrogen nucleus, which has a charge +e, is situated to the left of a carbon nucleus, which has a charge +6e. Which statement is true?

a. The electrical force experienced by the hydrogen nucleus is to the left, and the magnitude is equal to the force exerted on the carbon nucleus.

b. The electrical force experienced by the hydrogen nucleus is to the left, and the magnitude is greater than the force exerted on the carbon nucleus.

c. The electrical force experienced by the hydrogen nucleus is to the left, and the magnitude is less than the force exerted on the carbon nucleus.

d. The electrical force experienced by the hydrogen nucleus is to the right, and the magnitude is equal to the force exerted on the carbon nucleus.

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CP Physic Final Exam Review8. Two point charges, Q1 and Q2, are separated by a distance R. If the distance between the

two spheres is doubled, what happens to the electrical force that each charge exerts on the other one?

a. It increases by a factor of 1/2.b. It increases by a factor of 1/4.c. It is reduced by a factor of 1/8.d. It increases by a factor of 1/16.e. It remains the same.

9. The electric field at point P due to a point charge Q a distance R away from P has a magnitude E. If the charge Q is doubled, the magnitude of E

a. It increases by a factor of 2.b. It increases by a factor of 4.c. It is reduced by a factor of 8.d. It increases by a factor of 16.e. It remains the same.

10. The electric field at point P due to a point charge Q a distance R away from P has a magnitude E. If the distance is doubled, the magnitude of E

a. It increases by a factor of 1/2.b. It increases by a factor of 1/4.c. It is reduced by a factor of 1/8.d. It increases by a factor of 1/16.e. It remains the same.

11. A student has a circuit that is missing a component at location X, as shown in the diagram below.

The student wants component Y to warm up after the switch is closed. Which of the following components should the student add to the circuit at location X?

12. The current at point E is _________ compared to the current at point A?a. greater thanb. Less thanc. equal tod. can not determine

13. Which of the following will cause the current through an electrical circuit to decrease? a. add a light bulb in parallelb. decrease the resistancec. increase the voltaged. increase the resistance

14. Three identical light bulbs are connected to a battery as shown at the right. Which one of the following statements is true?

a. All three bulbs will have the same brightness. b. The bulb between X and Y will be the brightest.c. The bulb between Y and Z will be the brightest.d. The bulb between Z and the battery will be the brightest.

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CP Physic Final Exam Review15. Compare circuit X and Y below. Each is powered by a 12-volt

battery. The voltage drop across the 12-ohm resistor in circuit Y is ____ the voltage drop across the single resistor in X.

a. smaller than b. larger thanc. the same as

16. A 12-V battery, a 12-ohm resistor and a light bulb are connected as shown in circuit X. A 6-ohm resistor is added to the 12-ohm resistor and bulb to create circuit Y as shown. The bulb will appear ____.

a. dimmer in circuit X b. dimmer in circuit Yc. the same brightness in both circuits

17. A 12-V battery and a 12-ohm resistor are connected as shown in circuit. A 6-ohm resistor is added to the 12-ohm resistor to create circuit Y as shown. The voltage drop across the 6-ohm resistor in circuit Y is ____ that across the resistor in X.

a. larger than b. smaller thanc. the same as

18. Current I enters a resistor as shown. At which point is the potential higher, point A or at point B?

a. Ab. BC. equald. can not determine.

19. Current I enters a resistor as shown above. At which point is the current greater at point A or at point B?

a. Ab. Bc. equald. can not determine.

20. When unequal resistors are connected in series across an ideal battery,a. the same power is dissipated in each one.b. the potential difference across each is the same.c. the current flowing in each is the same.d. the equivalent resistance of the circuit is less than that of the smallest resistor.e. the equivalent resistance of the circuit is equal to the average of all the resistances.

21. When unequal resistors are connected in parallel in a circuit,a. the same current always runs through each resistor.b. the potential drop is always the same across each resistor.c.the largest resistance has the largest current through it.d. the power generated in each resistor is the same.

22. Magnetic field lines travel from___________a. north pole to south pole through the magnetb. in a circle around the entire magnet, while never touching the magnetc. south pole to north pole outside the magnetd. north pole to south pole outside the magnet

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CP Physic Final Exam Review23. What happens when a magnet is cut in half?

a. it becomes demagnetizedb. You get one north and one south polec. you get monopolesd. you get two magnets

24. Magnetic domain are _______ inside a magnet

a. scattered.b. Alignedc. Misalignedd. Random

25. Which of the following is not illustrated in the picture above?

a. A current causes a magnetic fieldb. A magnetic field caused by a wire is stronger closer to

the wirec. Magnetic field lines form closed loopsd. Magnetic field lines point from north to south

26. If a nail that touches a magnet will

a. meltb. generate an electric currentc. demagnetize the magnetd. become magnetized

27. If there were no current in the wire in the figure shown on the right, what would the direction of the magnetic force be?

a. upb. downc. left d. righte. no force

28. In the picture shown on the right of a current carrying wire, what direction is the current in the wire?

a. leftb. rightc. upd. downe. unknown

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CP Physic Final Exam Review29. The graphs shown show the magnitude F of the force exerted by a spring as a function of the

distance x the spring has been stretched. For which one of the graphs does the spring obey Hooke's law?

A) Graph aB) Graph bC) Graph cD) Graph dE) Graph e

30. If you wanted to know how much the temperature of a particular piece of material would rise when a known amount of heat was added to it, which of the following quantities would be most helpful to know?

A) initial temperature

B) specific heat

C) density

D) coefficient of linear expansion

E) thermal conductivity

31. On a cold day, a piece of metal feels much colder to the touch than a piece of wood. This is due to the difference in which one of the following physical properties of these materials?

A) density

B) specific heat

C) emissivity

D) thermal conductivity

E) mass

32. The process in which heat flows by the mass movement of molecules from one place to another is known as

A) conduction.

B) convection.

C) radiation.

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CP Physic Final Exam Review

33. Steam is being emitted from a pot of boiling water. Just above the water the temperature of the steam is which one of the following temperatures?

a) Below 100 oC

b) 100 oC

c) Above 100 oC

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CP Physic Final Exam Review34. A student slowly heats a beaker of a liquid on a hot plate. The liquid has a boiling point of

78°C. The student makes the graph shown below from the data she records as the liquid is heating.

35. Which of the following statements best describes what happens to the molecules of liquid between 5 and 10 minutes of heating?

A. The mass of the molecules increases.

B. The molecules undergo a chemical change. C. The molecules change phase.

D. The average kinetic energy of the molecules decreases.

36. Hot cider is poured into a metal cup. Shortly thereafter, the handle of the cup becomes hot. This is due to the process of…

a. Conductionb. Convectionc. Radiationd. Osmosis

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Problems: You must show all work and follow the problem solving procedure to receive credit.

1. How many electrons are necessary to produce 2.0 C of negative charge? ANS:1.25x1019electrons

2. Two electrons on the surface of a metal can are 20mm apart. What is the magnitude of the electric force that they exert on each other? ANS: 5.8x10-25 N

3. When 1.0-μC point charge is 15 m from a second point charge, the force each one experiences a force of 1.0 μN. What is the magnitude of the second charge? ANS: 2.5x10-

8 C

4. An electron is placed in a uniform electric field of 4.5 x 104 N/C that points to the right. What are the magnitude and direction of the force on the electron? ANS: 7.2x10-15 N

5. The electric field at a point 2.8 cm from a small object points toward the object with a strength of 180,000 N/C. What is the object's charge q? ANS: 1.57x10-8 C

6. Two small identically charged balls are a certain distance apart. The vectors in the figure show the magnitude and direction of the electrostatic force on each ball due to the other one. Suppose that the charge on the left ball is now doubled (represented by two plus signs). Draw a diagram that represents the new electrostatic force on the two charges.

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7. The force of attraction that a -40.0 μC point charge exerts on a +108 μC point charge has magnitude 4.00 N. How far apart are these two charges? ANS:3.11 m

8. A proton is placed in an electric field of intensity 800 N/C. What are the magnitude and direction of the acceleration of the proton due to this field? (mass proton = 1.67 x 10-27kg)ANS: 8.0x1010 m/s

9. Two tiny particles having charges +20.0 μC and -8.00 μC are separated by a distance of 20.0 cm. What are the magnitude and direction of electric field midway between these two charges? ANS: -7.19 x 10 6 N/S

10. The potential difference between two square parallel plates is 4.00 V. If the plate separation is 6.00 cm and they each measure 1.5 m by 1.5 m, what is the magnitude of the electric field between the plates?

11. If 50 J of electric potential energy is stored when you move 10 C of charge from point A to point B, what is the magnitude of the electric potential difference between points A and B?

12. 3. A space probe approaches a planet, taking measurements as it goes. If it detects a potential difference of 6000 MV between the altitudes of 253,000 km and 276,000 km above the planet's surface, what is the approximate electric field strength produced by the

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CP Physic Final Exam Reviewplanet at 264,500 km above the surface? Assume the electric field strength is approximately constant at these altitudes.

13. 4. A battery maintains the electrical potential difference of 6.0-V between two large parallel metal plates separated by 1.0 mm. What is the strength of the electric field between the plates?

14. Household circuits are often wired with two size wires: 12-gauge and 14-gauge. The 12-gauge wire has a diameter of 1/12 inch while the 14-gauge wire has a diameter of 1/14 inch. Thus, 12-gauge wire has a wider cross section than 14-gauge wire. A 20-Amp circuit used for wall receptacles should be wired using 12-gauge wire and a 15-Amp circuit used for lighting and fan circuits should be wired using 14-gauge wire. Explain the physics behind such an electrical code.

15. The diagram at the right depicts a conducting wire. Two cross-sectional areas are located 50 cm apart. Every 2.0 seconds, 10 C of charge flow through each of these areas. What is the current through the wire? ANS: 5 Amps

16. Calculate the resistance and the current of a 7.5-Watt night light bulb plugged into a US household outlet (120 V). ANS: 1920 Ω

17. Determine the resistance of a 1-mile length of 12-gauge copper wire. Given: 1 mile = 1609 meters and diameter = 0.2117 cm. ANS:7.8Ω

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18. If all of the resistors in this circuit are 150Ω, determine the equivalent resistance from point a to b. ANS:150 Ω

19. A student performs an experiment to determine the relationships among voltage, current, and resistance. The student’s procedure includes the following steps. The table below shows the data collected.• Connect a 3.0 V battery to a 42 Ω resistor.• Measure the current using an ammeter and record the value.• Replace the 42 Ω resistor with a 54 Ω resistor, and then with a 66 Ω resistor, measuring and recording the current for each resistor.

Student Data

Resistance (Ω) Voltage (V) Current (I)42 3.0 0.07154 3.0 0.05656 3.0 0.045

a. Draw the circuit diagram for the original circuit with the 42Ω resistor and 3.0V battery, include the ammeter and voltmeter.

b. Describe in words the relationship between current and resistance, as voltage is held constant.

20. The student will investigate these relationships further using a different experiment.a. Write a procedure the student could use to test the relationships among voltage, current, and resistance if the only materials available for use are three 3.0 V batteries, one 30 Ω resistor, wire, and an ammeter.

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b. Make a data table similar to the Student’s Data table above to show the expected current measurements for your procedure.

c. Show your calculations and include units in your answer.

21. A long, straight wire is carrying a current of 5.81A in the positive x direction. What is the magnetic field 6.25 cm (in the positive y direction) from the wire? ANS: 1.8 x 10 -5 T

22. The magnetic field due to the current in a long, straight wire is 8.0 μT at a distance of 4.0 cm from the center of the wire. What is the current in the wire? (μ0 = 4π × 10-7 T • m/A)ANS: 1.6x10 12 A

23. A magnetic field of 9.4 x 10-5 T is created by a 250 turn solenoid that is 25cm long. What is the current required to produce the magnetic field in the solenoid? ANS: 0.074 A(a)

(b) What will happen to the magnetic field if you double the number of turns? ANS: increase

24. A straight wire that carries a 4.6-A current is in a uniform magnetic field oriented at right angles to the wire. If the magnetic field is 1.2 T and the force exerted on the wire is 0.60 N, what length of wire is in the magnetic field? ANS: 0.11 T

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CP Physic Final Exam Review25. Draw the magnetic field around the following items. Be sure to indicate the north and

south poles of the magnet and directions of the magnetic fields. For the compass shown (as circles) indicate the direction of the needle, remember the painted pole is North.

a. Bar Magnet

b. Electromagnet

c. Wire with current out of the page

d. Wire with current parallel to the page going from right to left.

26. At room temperature, a typical person loses energy to the surroundings at the rate of 62 W. If this energy loss has to be made up by an equivalent food intake, how many kilocalories (food calories) does this person need to consume every day just to make up this heat loss? (1 cal = 4.186 J) ANS: 1279.69 Kcal

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27. How much heat is required to raise the temperature of a 225-g lead ball from 15.0°C to 25.0°C? The specific heat of lead is 128 J/kg • K. ANS: 288 J

28. How much heat must be removed from 456 g of water at 25.0°C to change it into ice at -10.0°C? The specific heat of ice is 2090 J/kg • K, the latent heat of fusion of water is 33.5 × 104 J/kg, and the specific heat of water is 4186 J/kg • K. Ans: -190,950 J

37. The highest recorded temperature on Earth was 136ºF, at Azizia, Libya, in 1922.

(a) Express this temperature in degrees Celsius. ANS: 43.56 degrees Celsius

(b) Express this temperature in degrees kelvins. ANS: 316.71 degrees Celsius

38. A steel bridge is 1000 m long at -20°C in winter. What is the change in length when the temperature rises to 40°C in summer? The average coefficient of linear expansion of this steel is 13 × 10-6 C-1. ANS: 1000.78m

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39. How much heat is required to raise the temperature of a 225-g lead ball from 15.0°C to 25.0°C? ANS: 288 J

40. How much heat must be removed from 456 g of water at 0°C to change it into ice?ANS: 152,760 J

41. A technician needs to determine the amount of energy required to evaporate a vat containing 12 kg of alcohol. The alcohol enters the vat at room temperature 20 oC. How much energy is required, in Joules, to evaporate? ANS: 11,951,280 J

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CP Physic Final Exam ReviewEssay Question:

29. Explain the different ways that an object can be charged, make sure to include each method and an explanation why there is a transfer/seperation of charge.

30. We say that electric fields emanate from positive charges and terminate on negative charges throughout all space. That being the case, is it possible for a location in space to be absence of an electric field? If so explain how. If not, explain why.

31. What examples (plural) do we have to confirm the existence of a magnetic field around a current carrying wire?

32. Compare and contrast a bar magnet with an electromagnetic.

33. Compare and contrast magnetic poles and electric charges.

34. We have shown that electricity can create magnetism and magnetism can create electricity. Compare and contrast these two phenomena and state the relative importance of this relationship.

35. The mechanical energy of a falling ball stays the same, even though it is constantly speeding up. Similarly, if you throw a ball upward, it slows down, even through its mechanical energy stays the same. Explain the physics of how this happens.

36. Compare and contrast Heat and Temperature.

37. Briefly explain why a typical mercury thermometer works the way it does.

38. When you boil water, the temperature remains the same, even though you continue to add heat. Explain where this heat energy is going if it doesn’t increase the temperature of the water.

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Material Freezing Point (Co) Lf (cal/g) Lf (Joules/kg)Alcohol (ethyl) -144 24.9 1.04 x 105

Ammonia -75 108 4.53 x 105

Mercury -39 2.8 0.117 x 105

Ethylene Glycol -12 42 1.76 x 105

Water 0 79.7 3.34 x 105

Tin 232 13.8 0.578 x 105

Lead 327 5.5 0.23 x 105

Aluminum 658 94 3.94 x 105

Material Boiling Point (oC) Lv (cal/g) Lv (Joules/kg)Ammonia -33 327 13.7 x 105

Acetone 56 125 5.25 x 105

Alcohol 78 204 8.55 x 105

Water 100 540 22.6 x 105

Ethylene Glycol 197 191 8 x 105

Mercury 357 70.6 2.96 x 105

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Specific Heatof Common Substances

Materialcalorie

g oCJoule kg oC

Acetone 0.57 2390Olive oil 0.47 1970Mercury 0.033 138Hydrogen 3.4 14,246Helium 1.3 5450Steam 0.48 2010Nitrogen 0.24 1010Air 0.24 1010Oxygen 0.22 922Water 1.00 4190Alcohol (ethyl) 0.58 2430Ice (at 0o

C) 0.5 2090Wood 0.42 1760Aluminum 0.215 900Iron(Steel) 0.107 448Brass 0.092 385Lead 0.0305 128Silver 0.056 234Tin 0.055 230


Multiple Choice Answers

1. c2. b3. a4. c5. b6. a7. a8. b9. a10.b11.c12.c13.d14.a15.a16.c17.b18.a19.c20.c21.b22.d23.d24.b25.d26.d27.e28.a29.b30.b31.b32.b33.b34.none35.c36.a

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· web viewtwo tiny beads are 25 cm apart with no other charges or fields present. bead a carries...

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