Science 9 Ch 8PracticeName______

1.Circuit A
/ 2.Circuit B
/ 3.Circuit C

1.Circuit diagram / 2.Circuit diagram / 3.Circuit diagram

Complete the statements.

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a)If you increase the current, the:

  1. voltage will ______.

b)If you increase the voltage, the:

  1. current will ______.

c)If you increase the resistance, the:

  1. current will ______.
  2. voltage will ______.

d)If you decrease the resistance, the:

  1. current will ______.
  2. voltage will ______.

e)If you decrease the current, the:

  1. voltage will ______.

f)If you decrease the voltage, the:

  1. current will ______.

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Convert the following:

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a)17 A = _____mA

b)1.25 A = ____mA

c)156 mA = _____ A

d)12.4 mA = ____A

e)1700 Ω = ____ kΩ

f)35 kΩ = ____ Ω

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Give the value of each resistor indicated by the colour bands.

1st band colour

/

2nd band colour

/

3rd band colour

/

Work

/

Resistor Value ()

(a) / blue / green / red
(b) / violet / black / yellow
(c) / green / blue / brown
(d) / brown / red / black
(e) / grey / violet / orange
(f) / red / brown / red

True or False?

Read the statements given below. If the statement is true, write “T” on the line in front of the statement. If it is false,

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write “F” and rewrite the statement to make it true.

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____1. An electric circuit is a complete pathway through which electrons can flow.

____2. An electric load transforms light energy into electrical energy.

____3. Light bulbs, heaters, and batteries are all examples of electric loads.

____4. The wire through which electric current flows is a conductor.

____5. A switch is the source of electric potential energy in a circuit.

____6. Circuit diagrams use circuit symbols to illustrate actual electrical circuits.

____7. Current electricity is charge that remains stationary on an insulator.

____8. Electric current is the amount of charge passing a point in a conducting wire each second.

____9. Electric current is measured in volts.

____10. An ammeter is used to measure the current in a circuit.

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Ohm’s Law Calculations. Show Your Work!

1.What is the resistance of a toaster if a current of 12.5 A flows through it when it is connected
to 120 V? / 5.A flashlight bulb has a resistance of 4.0What current passes through the bulb if it is connected to 3.0 V?
2.A light bulb has a resistance of 90 What current flows through the bulb when it is connected to 120 V? / 6.What potential difference is necessary to produce a current of 0.60 A in a load that has a resistance of 25 
3.A current of 0.50 A flows through a light bulb that has a resistance of 18 What is the voltage across this light bulb? / 7.The current through a load in a circuit is 2.5 A. If the potential difference across the load is 75 V, what is the resistance of the load?
4.Only 2.5 × 103 A of current pass
through a portable CD player. If the CD player is operated by a 9.0 V battery, what is the resistance within the circuit? / 8.An automobile headlight has an average
resistance of 24 . Car batteries provide a potential difference of 12 V. What amount of current passes through the headlight?

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9.In a portable radio, 0.50 A of
current are flowing through a conductor that provides 18  of resistance. What potential difference is provided by the battery? / 10.A clothes dryer uses a 220 V power
source. The coils of the heater provide an average resistance of 12 . What amount of current is flowing through the heating coils?


Ohm’s Law Equations

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1. A current through a resistor in a circuit is 1.5 A. If the potential difference across the resistor is 6 V, what is the resistance of the resistor?

2. A toaster is plugged into a 120 V outlet. What is the resistance of the toaster if the current in the toaster is 10 A?

3. A light bulb with a resistance of 30 Ω is connected to a battery. If the current in the light bulb is 0.2 A, what is the voltage of the battery?

4. What is the current in a flashlight bulb with a resistance of 24 Ω if the voltage provided by the flashlight battery is 3 V?

5. An electric iron plugged into a wall socket has a resistance of 20 Ω. If the current in the iron is 6 A, what is the voltage provided by the wall socket?

6. A 1.2 A current flows through a 250 ohm resistor. Calculate the voltage across this resistor.

7. A 120 Ω resistor is connected to a 12 V battery. Calculate the current through the resistor.

8. An unknown resistor transforms 2.0 mA of current when connected to a 9.0 V battery. Calculate the value of this resistor.

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