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Current Electricity
What happens to the resistivity of semi-conductors with the increase of temperature?
The resistivity of a semiconductor decreases with increase in temperature.
Find the equivalent resistance between points A and B.
Let 12 
, 6 
and 4
b are connected in parallel.
Therefore, equivalent resistance is, 
That is, 
The relationship between the potential difference and the current in a conductor is stated in the form of a law.
i) Name the law.
ii) What does the slope of V-I graph for a conductor represent?
iii) Name the material used for making the connecting wire.
i) Ohm’s Law.
ii) The resistance of the conductor.
iii) Copper because it has less resistance.
A cell of emf 2 V and internal resistance 1.2 is connected with an ammeter of resistance 0.8 and two resistors of 4.5 and 9 is shown as in the diagram below:
i) What would be the reading on the ammeter?
ii) What is the potential difference across the terminals of the cell?
Given,
E = 2 V, r = 1.2 , R = external resistance
Let 4.5 
and 9 
are connected in parallel, then equivalent resistance becomes,
RP = 3 
Now, 0.8 
, and RP resistance in series, then total resistance is, 
i) Current in 0.8 
resistance, I = 
ii) Terminal voltage, V = E – I r = 2 – 0.4 × 1.2 = 2 – 0.48 = 1.52 Volt
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Mock Test Series
Mock Test Series