Questions on Characteristic Curves - Filament Lamp
Q2.
A filament lamp rated 12 V, 1.0 A has a resistance of 4.0
when it carries no current.
(a) On the axes below, sketch the form of the current against voltage characteristic for this lamp.

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corrct shape in one quadrant 
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symmetrical trace in other 
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Plotted point (1.0, 1.2) 
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Plotted point (0, 0) 
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Gradient at origin of 4.0 
(4)
(b) The filament lamp is one example of a non-ohmic device.
(i) State what is meant by the term non-ohmic.
In a non-ohmic component V is not directly proportional to I - in other words the resistance is not constant - it varies with potential difference applied.
(1)
(ii) Name one other example of a non-ohmic device.
semiconductor diode 
(1)
(Total 6 marks)