Revision sheet for the third final* exam
Physics / Grade 12
Student’s name: ……………………………………………………… Date: 8/5/2017
*RequiredMaterial :Chapter 16 / Sections: 2 and 3; Chapter 18 / Section: 2; Chapter 19 / Sections: 1, 2, and 3
Textbook Pages: (554-567), (635-644), (664-675)
Common Core Standards: 12.Phy.5a, 12.Phy.5b, 12.Phy.5k, 12.Phy.5n
Chapter.16 / Section.2: Electric Force
Write the letter of the correct answer in the space provided.
_____1An electric force F exists between two objects, both having the charge q. If the charge on one object is doubled to 2q, the force between the objects becomes
a.F c. 2F.
b.F d. 4F.
_____2.An electric force F exists between two objects separated from each other by distance r. If the distance is decreased to 0.5r, the force between the two objects becomes
a.F c. 2F
b.F d. 4F.
_____3.Two point charges, initially 2 cm apart, are moved to a distance of 8 cm apart. By what factor does the resulting electric force between them change?
a.2 c.
b.4 d.
_____4.Two charged objects are near each other. One has a charge of
2.0 105 C and the other has a charge of 4.0 105 C. If the first charge doubles to 4.0 105 C, and the second charge doubles to
8.0 105 the force between the charges changes by a factor of
a.16 c. 2
b.4 d. No change occurs.
_____5.Electric force and gravitational force are alike in that both forces
a.depend on charge.c.act only when objects are
touching.
b.depend on mass.d.are field forces.
_____6.The diagram above represents an array of point charges of the magnitudes shown. Assume that no net force acts on charge q3.
What can you say about the sign and magnitude of charge q3?
a.The charge must be positive and less than the charge on q1 and q2.
b.The charge must be positive and the same as the charge on q1 and q2.
c.The charge must be negative and the same as the charge on q1 and q2.
d.The charge can have any sign and any magnitude.
7. Two point charges having charge values of 4.0 106 C and 8.0 106 C, respectively, are separated by 2.4 102 m. What is the value of the mutual force between them? (kc = 8.99 109 Nm2/C2)
8. Two electrostatic point charges of 13.0 µC and 16.0 µC exert repulsive forces on each other of 12.5 N. What is the distance between the two charges?
9. Suppose two equal charges are separated by 6.5 1011 m. If the magnitude of the electric force between the charges is 9.92 104 N, what is the value of q?
10. What is an electric force?
…………………………………………………………………………………………………
…………………………………………………………………………………………………
11. What determine the direction of the electric force between two charges?
…………………………………………………………………………………………………
Chapter.16 / Section.3: The Electric Field
Write the letter of the correct answer in the space provided.
_____1.Which of the following would be the best to use to determine whether an electric field is present around an object?
a.a magnetized pin
b.light from a lamp
c.a charged table tennis ball
d.a mass suspended from a spring scale
_____2.Which of the following units is used to state the strength of an electric field?
a.coulombs per cubic meter
b.coulombs per newton
c.newtons per coulomb
d.meters per coulomb
_____3.The strength of an electric field around a charged object depends on both the magnitude of the charge and
a.the magnitude of a test charge.
b.the sign of the object’s charge.
c.the distance from the object.
d.the volume of space around the object.
_____4.The electric fields of two charges, A and B, are represented by diagrams showing electric field lines. If charge B is greater than charge A, the diagram of charge B will have ______than the diagram of charge A.
a.more lines per unit area
b.longer field lines
c.straighter field lines
d.more curved field lines
_____5.The diagram on the right shows the electric field lines around two charges that have been brought near each other. From the diagram you can infer that the charge of the left is ______than the charge on the right.
a.negative and smaller in magnitude
b.negative and larger in magnitude
c.positive and smaller in magnitude
d.positive and larger in magnitude
6. Find the electric field at a point midway between two charges of 30 109 C and 60 109 C separated by a distance of 30 cm?(kc = 8.99 109 Nm2/C2)
7. An electric field of 2250 N/C is produced by a charge of 4.82 1011C.
For this field strength, what is the distance to the charge? (kc = 8.99 109 Nm2/C2)
10. What is an electric field?
…………………………………………………………………………………………………
…………………………………………………………………………………………………
Chapter.18 / Section.2: Resistors in Series or in Parallel
Ohm’s Law: V=IR
_____1.Several resistors are wired in a circuit so that there is a single path for the flow of electric current. What type of circuit is this?
a.electronic circuit
b.series circuit
c.parallel circuit
d.short circuit
_____2.Five resistors are wired in a series circuit. How does the equivalent resistance of the circuit compare to the resistances of the individual resistors?
a.The equivalent resistance is greater than any single resistance.
b.The equivalent resistance is less than any single resistance.
c.The equivalent resistance is the same as any single resistance.
d.The equivalent resistance is one-fifth the value of any single resistance.
_____3.Several resistors are wired in series. What is true about this circuit?
a.The sum of the currents through each of the resistors is equal to the total circuit current.
b.The total circuit current is the same as the current through any one of the resistors.
c.The voltage across any resistor is the same as the voltage of the power supply.
d.The current in any single resistor is determined by its resistance and the voltage of the power supply.
_____4.Two resistors and a battery are wired in a series circuit. One resistor has twice the resistance of the other resistor. What is true about the voltage across the two resistors?
a.Each resistor has half the battery voltage across it.
b.One-third of the battery voltage is across the higher value resistor.
c.One-third of the battery voltage is across the lower value resistor.
d.Two-thirds of the battery voltage is across the lower value resistor.
_____5.The current through one resistor in a parallel resistor circuit is always
a.the same as the current in the other resistors in the circuit.
b.less than the total current in the circuit.
c.equal to the total current in the circuit.
d.more than the total current in the circuit.
6. Three resistors with values of 27 , 81 , 16 , respectively, are connected in parallel. What is their equivalent resistance?
7. Three bulbs are wired in series: one bulb has a resistance of 56 , one bulb has a resistance of 82 , and one bulb has a resistance of 24 . If the voltage across the circuit is 9.0 V, what is the current through the circuit?
8. A 24- resistor is connected in series with another resistor across a 3.0-V battery. The current in the circuit is 62 mA. Calculate the value of the unknown resistance.
9. Four resistors with values of 4.0 , 6.0 ,8.0 , and 12.0 , are connected in series with 12.0 V battery.
a. Calculate the equivalent resistance.
b. Calculate the current in the circuit.
c. What is the current in each resistor?
d. What is the potential difference across each resistor?
10. Three resistors with values of 3.0 , 7.0 ,and 9.0 , are connected in parallel with 9.0V battery.
a. Calculate the equivalent resistance of the circuit.
b. What is the potential difference across each resistor?
c. Calculate the current in the circuit.
d. What is the current in each resistor?
11. Two bulbs are wired in parallel: one bulb has a resistance of 3.3 , and the other bulb has a resistance of 4.3 . If the voltage across the circuit is 1.5 V, what is the current through each bulb?
12.A 3.3 resistor is connected in parallel with another resistor across a 3.0 V battery. The current in the circuit is 1.41 A. Calculate the value of the unknown resistance.
13. Write the definitions of the following terms:
- Series: ………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………
-Parallel:
………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………
Chapter.19 / Section.1: Magnets and Magnetic Field
Write the letter of the correct answer in the space provided.
_____1.Which of the following statements correctly describes the behavior of magnets?
a.Like poles attract each other, and unlike poles repel each other.
b.Like poles repel each other, and unlike poles attract each other.
c.Both like and unlike poles can attract and repel each other depending on the surrounding materials.
d.none of the above
_____2.What do physicists call large groups of atoms whose net spins are aligned because of strong coupling between neighboring atoms?
a.magnetic zones
b.magnetic regions
c.magnetic sectors
d.magnetic domains
_____3.Which of the following statements about magnetic fields, B, is not true?
a.Magnetic fields are vector quantities.
b.Magnetic fields have both magnitude and direction.
c.Magnetic field strength increases as the distance from the magnetic source increases.
d.Magnetic fields are regions in which magnetic forces can be detected.
_____4.How is the direction of a magnetic field, B, defined at any location?
a.the direction toward which the south pole of a compass needle points
b.the direction toward which the north pole of a compass needle points
c.the direction that is parallel to the imaginary magnetic field lines
d.the direction that is perpendicular to Earth’s magnetic field
_____5.What describes M?
a.magnetic flux
b.the number of field lines that cross a certain area
c.ABcos
d.all of the above.
_____6.Since more magnetic field lines cross the area that is near the pole of a magnet, what does this indicate about the magnetic field strength in that location?
a.It is stronger.
b.It is weaker.
c.It is entering the magnet.
d.It is leaving the magnet.
_____7.Which of the following statements about magnetic field lines is not true?
a.Magnetic field lines form open or closed loops.
b.Magnetic field lines appear to begin at the north pole of a magnet.
c.Magnetic field lines have no beginning or end.
d.Magnetic field lines appear to end at the south pole of a magnet
8.For each of the figures below, indicate whether the magnets will attract or repel one another.
9.Draw magnetic field lines around the magnet below. Indicate the relative strength of the magnetic field by drawing more lines where the magnetic field is strongest.
10. What is the minimum number of poles for a magnet? ………………………..
11. When you break a magnet in half, how many poles does each piece have? ………….
12. The north pole of a magnet is attracted to the geographic North Pole of Earth, yet like poles repel. Explain this.
……………………………………………………………………………………………………………………………………………………………………………………………………
13. Write the definitions of the following terms:
- magnetic domain: ………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………
-magnetic field:
……………………………………………………………………………………………………………………………………………………………………………………………………
Chapter.19 / Section.2: Magnetism from Electricity
Write the letter of the correct answer in the space provided.
_____1.Which of the following terms correctly describes the shape of the magnetic field around a long, straight current-carrying wire?
a.cylindrical
b.parallel
c.perpendicular
d.elliptical
_____2.In what direction do compass needles deflect in relation to the concentric circles of the magnetic field that is found around a current-carrying wire?
a.away from the concentric circles
b.perpendicular to the concentric circles
c.toward Earth’s North Pole irrespective of the concentric circles
d.tangential to the concentric circles
_____3.The right-hand rule states that the thumb of the right hand is to be placed in what direction when grasping a wire?
a.in a direction opposite of the current
b.in the direction of the current
c.in the direction of Earth’s magnetic north pole
d.none of the above
_____4.According to the right-hand rule, in what direction will the fingers curl?
a.in the direction of the current
b.in the direction of the magnetic field, B
c.in the direction of the magnetic field’s movement
d.in the direction of the magnetic field’s force
_____5.Which of the following statements about the magnetic field, B, around a current-carrying wire is not true?
a.B is proportional to the current in the wire.
b.B is inversely proportional to the distance from the wire.
c.The lines of B form concentric circles about the wire.
d.B is independent of the current in the wire.
Chapter.19 / Section.3: Magnetic Force
Write the letter of the correct answer in the space provided.
_____1.When does the magnetic force on a charge moving through a constant magnetic field reach its maximum value?
a.when the charge moves parallel to the magnetic field
b.when the charge moves at any angle to the magnetic field
c.when the charge moves perpendicular to the magnetic field
d.when the charge is stationary to the magnetic field
_____2.Given the following equation, , which of the following statements is true?
a.The magnetic field, B, is directly proportional to q.
b.The magnetic field, B, is directly proportional to v.
c.The magnetic field, B, is directly proportional to Fmagnetic.
d.The magnetic field, B, is directly proportional to Fmagnetic, q, and v.
_____3.Which of the following statements about the right-hand rule is not true?
a.The fingers indicate the direction of the magnetic field.
b.The thumb indicates the direction of a particle’s movement in the magnetic field.
c.The direction of the magnetic force is always parallel to the magnetic field.
d.The direction of the magnetic force exerted on a proton is out of the palm of the hand.
4.If Fmagnetic = 3.8 1013 N,q = 1.60 1019 C, and v = 2.4 106 m/s, use the equation, , to find the magnitude of the magnetic field, B.
5. Determine the velocity of a proton that is moving perpendicular to a magnetic field whose magnitude is 3.5 103 Tand magnetic force is 8.2 1016 N. Recall that a proton’s charge is 1.60 1019 C.
6. A proton moves at right angles to a uniform magnetic field of 0.8 T. If the speed of the proton is 3.0 107 m/s, what is the magnetic force exerted on the proton?