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P2: Quiz 6
Click here for a printable PDF of the graphs and circuits in this quiz.

1)
a) Draw the symbol for a thermistor.
b) What are thermistors generally used as?
c) Use the graph below to show how the resistance of a thermistor changes as temperature increases.
​d)
i) Out of cold and hot temperatures, when is the resistance of a thermistor the highest?
ii) Out of cold and hot temperatures, when is the resistance of a thermistor the lowest?
e) Give two products that thermistors are used in.  
 
 
2)
a)
i) What does LDR stand for?
ii) Draw the symbol for an LDR.
b) What are LDRs generally used as?
c) Use the graph below to show how the resistance of an LDR changes as light intensity increases.
​d)
i) Out of dark and light conditions, when is the resistance of an LDR the highest?
ii) Out of dark and light conditions, when is the resistance of an LDR the lowest?
e) Give two products that LDRs are used in. 


​​3) The circuit below is for an automatic light that turns on at night.
​a) Explain why the light turns on/ is very bright in dark conditions. 
b) Explain why the light turns off/ is very dim in light conditions.
​ 
 
4) The circuit below is used to control an automatic fan in a room. When the room is hot, the fan turns on. And when the room is cold, the fan turns off.
a) Explain why the fan turns on when it is hot.
b) Explain why the fan turns off when it is cold.