1. 
Resistance can be described as the:
A. 
opposition to current flow 
B. 
resist rate of the voltage 
C. 
current acceptability of a voltage 
D. 
opposition to voltage flow 

2. 
The resistance of a material is most commonly determined by four factorslength, crosssectional area, type of material and:

3. 
The resistance of a conductor is proportional to its:

4. 
The resistance of a conductor is inversely proportional to its:

5. 
Look at the following table:
The above table gives the resistivity of some common materials used in the electrical industry. The best conductor shown on the table is:

6. 
Resistivity of a material is defined as the:
A. 
amount of opposition to a flow of resistance through 1 meter cube of the material 
B. 
resistance between the opposite faces of a 1 meter cube at a specified temperature 
C. 
resistance of 100 meters of 1.5 mm^{2} copper cable at a specified temperature 
D. 
resistance between two faces of a 1 mm^{2} block of that material at 20 °C 

7. 
The following formula can be used to determine the resistance of a length of conductor.
In the formula the symbol ρ stands for the:
A. 
crosssectional area of the conductor in m^{2} 
B. 
product of the length of the conductor in meters 
C. 
resistivity of the material on ohmmeters 
D. 
resistance of the conductor ohms per meter 

8. 
A copper cable has a length of 450 m and a crosssectional area of 4.0 mm^{2}. If the resistivity of the copper is 1.72E8 Ωm, then the resistance of this cable will be:

9. 
A 10 Ω resistor is to be made from manganin wire with crosssectional area of 0.2 mm^{2}. If manganin has a resistivity of 48 E–8 Ωm, then the required length of this size manganin wire will be:

10. 
The temperature coefficient of resistance of a material is defined as the change in:
A. 
temperature per degree per ohm 
B. 
resistance per ohm per degree Celsius 
C. 
crosssectional area per meter per degree Celsius 
D. 
length per meter per ohm resistance 

11. 
For some materials, an increase in temperature causes an increase in resistance; these materials are said to have a:
A. 
standard temperature coefficient 
B. 
negative temperature coefficient 
C. 
positive temperature coefficient 
D. 
ambient temperature coefficient 

12. 
Look at the following graph:
The above graph shows the effect of an increase in temperature on a copper conductor. The graph shows that the increase of resistance plotted against temperature is:

13. 
The inferred zero formula for determining the resistance of a copper conductor is shown:
In the formula, the term t_{2}stands for the:
A. 
final temperature of the conductor 
B. 
initial temperature of the conductor 
C. 
final resistance of the conductor 
D. 
initial resistance of the conductor 

14. 
The resistance of a coil of copper wire is 30 Ω at 15ºC. Its resistance at 75ºC will be:

15. 
An electric motor has a winding resistance of 15 Ω at 20ºC. After running up to temperature at full load the resistance is measured as 19 Ω. The temperature of the windings will now be:

16. 
The temperature coefficient of resistance is defined as the change in:
A. 
temperature per degree per ohm resistance 
B. 
the coefficient of current allowed through a resistance 
C. 
the resistance of a voltage path per change in current in amperes 
D. 
resistance per ohm per degree change in temperature 

17. 
The above formula can be used to determine the resistance of a conductor using the temperature coefficient of resistance method.
In the formula the term R_{1} stands for the:
A. 
initial resistance of the conductor 
B. 
final resistance of the conductor 
C. 
initial temperature of the conductor 
D. 
final temperature of the conductor 

18. 
If copper conductor has a resistance of 15 Ω at 0ºC, then using the temperature coefficient of resistance method (Note: Consider the temperature coefficient of resistance of copper to be 0.004 27 Ω/Ω/ºC at 0°C.), its resistance at 20ºC will be:

19. 
The supply to a 15A airconditioning unit consists of copper conductors with a crosssectional area of 2.5 mm^{2} and a total resistance of 0.38 Ω. When the airconditioner is operating, the power lost in the conductors will be:

20. 
Many materials produce an effect known as ‘superconductivity’ when they are cooled below a certain temperature. At the critical temperature:
A. 
electrons cannot pass through the material 
B. 
the material exhibits a super resistance of a very high ohmic value 
C. 
all the electrons speed up and reach a superhigh temperature 
D. 
electrons can pass through the material with seemingly zero resistance 

21. 
When current flows through a conductor, the conductor will heat up. If the conductor temperature exceeds the insulation rating of the cable then the:
A. 
insulation can be damaged 
B. 
circuit current will stop 
C. 
cable will begin to cool 
D. 
circuit current increase 

22. 
A resistance of 120 Ω is required to carry 200 mA of current. The value of power dissipation required by this resistor is:

23. 
Smaller value resistors, from 5 watts to several hundred watts, are commonly:
B. 
carbon film type with conductive paint 
C. 
wire wound on a ceramic former 
D. 
metaloxide on a phenolic base 

24. 
The E12 range of preferred values of resistors is based on a tolerance of:

25. 
Look at the following diagram:
The size of the above resistor is:

26. 
Look at the following diagram:
The above diagram shows the characteristic for a typical PTC thermistor. For an increase in temperature, the resistance of the thermistor will:

27. 
Look at the following diagram:
The above diagram shows the characteristic for a typical NTC thermistor. For an increase in temperature between 50°C and 60°C, the resistance of the thermistor:
B. 
decreases at the knee point 
C. 
decreases in an almost linear manner 
D. 
will be equal to the resistance at 20°C 

28. 
The voltage dependent resistor normally only conducts when the:
A. 
circuit current exceeds a certain designed value 
B. 
power rating of the supply is exceeded 
C. 
supply voltage needs boosting 
D. 
supply voltage exceeds a designed limit 

29. 
Lightdependent resistors are used to detect light levels such as in PE (photoelectric) cells on power poles to turn street lights on and off, or to control other night lighting. When light falls on the resistor:
A. 
its resistance changes 
C. 
it generates a current 
D. 
its resistance always remain the same 

30. 
Liquid resistors are often used in motor starters. One advantage of liquid resistance is that the resistance value:
A. 
increases as the temperature rises 
B. 
decreases as the temperature rises 
C. 
decreases as the temperature decreases 
D. 
increases as the temperature increases 
