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Academic Year: 2018/2019 – Term 3

Physics / Grade 12

Revision Sheet / Final Exam

Student’s name: ……………………………………………………… Date: 12 / 5 / 2019

*Required Material:

Chapter 16 / Sections: 2 & 3 ; Textbook Pages: (554-567)

Chapter 18 / Sections: 1, 2 & 3 ; Textbook Pages: (628-661)

Chapter 19 / Section: 3 ; Textbook Pages: (673-679)

Chapter.16 / Section.2: Electric Force

1. 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)

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2. 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?

3. 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?

4. Consider three point charges on the x-axis: q1 4.92 109

C is at the origin,

q2 6.99 108

C is at 2.60 101

m, and q3 5.65 109

C is at 1.40 m. Find

the magnitude and direction of the resultant force on q1.

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Chapter.16 / Section.3: The Electric Field

1. 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?

2. An electric field of 2250 N/C is produced by a charge of 4.82 1011 C.

For this field strength, what is the distance to the charge?

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Chapter.18: Circuits and Circuits Elements

Ohm’s Law: V=IR

1.Three resistors with values of 27 , 81 , 16 , respectively, are connected in parallel.

What is their equivalent resistance?

2.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?

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3.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.

4. 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?

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5. 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?

6. 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?

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7. 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.

8. What will be the net current for the circuit shown at right?

9. Determine the equivalent

resistance of the complex

circuit shown at right.

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10. Determine the equivalent resistance

of the complex circuit shown at right.

Chapter.19 / Section.3: Magnetic Force

1. Write the letter of the correct answer in the space provided

_____ 1. Given the following equation,

B Fmagnetic

qv, 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.

_____ 2. If Fmagnetic = 3.8 1013 N, q = 1.60 1019 C, and v = 2.4 106 m/s, use the

equation,

B Fmagnetic

qv, to find the magnitude of the magnetic field, B.

a. 9.9 1011 T

b. 9.9 1027 T

c. 5.7 1039 T

d. 0.99 T

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_____ 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. According to the right-hand rule, what is the direction of the force on an electron?

a. out of the palm of the hand

b. out of the back of the hand

c. in the direction of the thumb

d. in the direction of the fingers

_____ 5. What path does a positively charged particle moving perpendicularly to a uniform

magnetic field follow?

a. erratic

b. helical

c. straight

d. circular

_____ 6. Consider two long, straight, parallel wires, each carrying a current I. If the

currents move in opposite directions,

a. the two wires will attract each other.

b. the two wires will repel each other.

c. the two wires will exert a torque on each other.

d. neither wire will exert a force on the other.

_____ 7. Consider two long, straight, parallel wires, each carrying a current I. If the

currents move in the same direction,

a. the two wires will attract each other.

b. the two wires will repel each other.

c. the two wires will exert a torque on each other.

d. neither wire will exert a force on the other.

2. State the definition of the magnetic force.

……………………………………………………………………………………………….........

……………………………………………………………………………………………….........

……………………………………………………………………………………………….........

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3. Find the direction of the force on a proton moving through the magnetic field shown on

the right. Then name the rule that you used and elaborate it.

4. For each situation below, use the movement of the positively charged particle and the

direction of the magnetic force acting on it to find the direction of the magnetic field.

( /3)

(a) …………………….. (b)………………….. (c)………………………..

5. An electron in a cathode ray tube (found in many televisions) moving at a speed

of 1.2 106 m/s has a magnetic force of 1.2 1017 N acting on it. What is the magnitude

of the magnetic field perpendicular to the electron’s path?

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6. The magnetic field in the Crab Nebula is about 1 108 T. If an electron moving

perpendicular to this field is affected by a magnetic force of 3.2 1022 N, what is the

electron’s speed?

7. Suppose an electron moves at a speed of 2.2 106 m/s on the surface of the Sun. Suppose

the Sun has a magnetic field of 1.1 102 T perpendicular to the electron’s path. What is

the magnetic force exerted on the electron by the Sun?

8. A fax machine requires 1.4 A of current to pass through a 2 m cable in order to work. If

the magnetic field perpendicular to the cable is 3.6 10-4 T, what is the magnetic force

exerted on the cable?

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9. A magician wants to build a device that will allow him to levitate for his magic act. His

device has a wire 10 m long bent into a loop. If the magician’s mass is 75 kg, and Earth’s

magnetic field (perpendicular to the wire) is 4.8 104

T, how much current must move

through the wire for the magician to levitate?