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Class Period:
GTT (8th) – MAGIC OF ELECTRONS FINAL EXAM
REVIEW
1. What are the differences between an insulator and a conductor? What types of
material make good insulators? Good conductors?
Insulator: any material that doesn’t allow the flow of electricity through it. Dull and
brittle. Good insulators include plastic, rubber, and glass
Conductor: any device that allows current to flow through it easily. Shiny and
malleable. Good conductors include gold, and copper
2. Name and be able to label the parts of a DC motor?
Brushes
Battery
Armature
Permanent Magnet
Commutator
3. Define an electromagnet and how does it work?
When you send electrical current through a coil of wire it becomes a magnet. You
can also wrap the coil around an iron core and make the iron a magnet.
4. What is a key component to a DC motor working?
Magnetism is key to making a DC motor working
5. What are the differences between AC and DC currents?
AC – alternating current generated from power plants that flows back and forth
DC – direct current generated from batteries that only flows in one direction
6. Define voltage, resistance, and current and how are they measured and in what
units?
Voltage: the force or pressure behind the movement of electrons measured in Volts
Resistance: the opposition of current flow measured in Ohms
Current: the flow of electric charge measured in Amperes or Amps
7. What is Ohm’s law and how do we use it?
𝑉 =𝐼×𝑅
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8. What are the different parts of an atom and define them.
Protons: positively charged particles found in the nucleus
Neutrons: uncharged particles found in the nucleus
Electrons: negatively charged particles orbiting the nucleus
9. List at least two characteristics of the CPU, memory, and hard drive of a computer
CPU: processor or brain on the computer, processing speed measured in MHz or
GHz, located on the motherboard
Memory: system’s short term memory, memory disappears when the computer is
turned off, more memory means more things a computer can do at the same time
Hard Drive: system’s long term storage, faster hard drives mean faster loading
times, come as hard disk drives or solid state drives
10. What are the three ways that circuits can be hooked up and how do they look?
Series circuit
One path for the electricity to flow
Parallel Circuit
More than one path for electricity to flow
Combination circuit
Contains both series and parallel branches
11. Name, define, and draw the various electrical components we learned about.
Name
Battery/Power Source
Symbol
Definition
A source of electrical
energy
Lamp
A device that produces
light when electricity
flows through it
Slide Switch
a component that opens
or closes a circuit when
slid into place
Pushbutton Switch
a component that opens
or closes a circuit when
pressed
Motor
Device that converts
electrical to mechanical
energy
Diode
Device that permits
electrical flow only in
one direction
LED
Device that emits light
when electricity flows
through it in the correct
direction
Fixed Resistor
a device with a set value
that opposes the flow of
electricity
Capacitor
Device that stores and
releases electrical
energy rapidly
12. How is the binary number system different from the decimal system?
The Decimal system uses combinations of the digits 0-9 in order to generate
numbers. It is the number system we use on a regular basis
The Binary number system uses combinations of the digits 0 and 1 to generate
numbers, letters, and symbols. Typically it is put in a stream of eight 1’s and 0’s
which is called a byte
13. What does STEM stand for?
Science Technology Engineering Mathematics
14. Convert the following binary code to a decimal number 011000110.
0
1
1
0
0
0
1
1
0
198
Solution: _____
15. Convert the decimal number 157 to binary code.
0
0
1
0
0
1
0010011101
Solution: _______________________________
1
1
0
1