Basic Electricity and Electronics
Module One – Terms and Definitions
1. Coulomb – is the unit of electrical charge
2. ( R ) Resistance – is the opposition to current flow. Measured in Ohms
3. (I) Current – is the movement of electrons (Coulombs per sec). Measured in
Amps
4. ( V ) Voltage - – is a potential difference between two points. Measured in
Volts
5. ( J ) Joule - is a unit of work. Measured in Joules
6. Power – work per unit of time. (Joules per second). Measured in Watts
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Work (units : joules)
refers to an activity involving a force and movement in the directon of the force.
A force of 20 newtons pushing an object 5 meters in the direction of the force
does 100 joules of work.
Energy (units : joules)
is the capacity for doing work. You must have energy to accomplish work - it is
like the "currency" for performing work. To do 100 joules of work, you must
expend 100 joules of energy.
Power (units : watts = joules/second)
is the rate of doing work or the rate of using energy, which are numerically the
same. If you do 100 joules of work in one second (using 100 joules of energy),
the power is 100 watts.
7. A volt is a/an:
a.
b.
c.
d.
Potential difference between two points
Unit of charge on an electron
Rate of flow of charge
Opposition to current flow
8. How many forms of Ohm’s Law are there?
a.
b.
c.
d.
One
Two
Three
Four
9. Energy is:
a.
b.
c.
d.
The fundamental ability to do work
The rate at which energy is used
The amount when one joule is used in one second
The maximum amount of power dissipated without damage
11. An electrical load is:
a.
b.
c.
d.
Any weight being carried
The amount of horsepower in a circuit
Any resistive element connected to a power supply
Taking more than four classes a semester
12. Which of the following is a unit of power?
a.
b.
c.
d.
Joule
Joule per second
Joule-second
Volt-ohm
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13. When the voltage across a resister is doubled, the current will:
a.
b.
c.
d.
Triple
Halve
Double
Not change
14. When the resistance in a circuit is doubled, the current will:
a.
b.
c.
d.
Triple
Halve
Double
Not change
17. What performs the work in an electric circuit?
a.
b.
c.
d.
Heat
Voltage
A resistor
Current
18. What is the definition of current?
a.
b.
c.
d.
The movement of electrons
Force created by the buildup of charge
Force times distance
A twisting or rotary force
19. What is the definition of voltage?
a.
b.
c.
d.
The movement of electrons
Force created by the buildup of charge
Force times distance
A twisting or rotary force
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20. What is resistance?
a.
b.
c.
d.
The interaction of two magnetic fields
Conversion of mechanical energy into electrical energy
An imbalance between electrons and protons
The opposition to current flow
21. What is the formula for Ohm’s Law?
a.
b.
c.
d.
P=VI
I=V/R
F=MA
I = V2 R
24. The unit of resistance is the:
a.
b.
c.
d.
Coulomb
Joule
Ampere
Ohm
25. The unit of electrical charge is the:
a.
b.
c.
d.
Coulomb
Joule
Ampere
Ohm
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26. A circuit has a 12 V power supply and a 1 kΩ resistor. What is the current?
I = V/R = 12V divided by 1000Ω= .012 A or 12 mA
27. A circuit has a 42 kΩ resistor and 8 mA of current. What is the voltage?
V=IXR
= .008 A X 42,000Ω = 336 V
28. A circuit has 520 milli amps of current and 240 volts. What is the
resistance?
R = V/I
= 240V divided by .52A = 461.5Ω
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