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A resistor is in left gap and a NTC semiconductor is in right gap of a meter bridge.Balancing length is noted l.Both are heated so that change of resistance in them is the same .Now balancing length is A.equal to l B.greater than l C.less than l D.depends on temperature change

A resistor is in left gap and a NTC semiconductor is in right gap of a meter bridge.Balancing length is noted l.Both are heated so that change of resistance in them is the same .Now balancing length is
A.equal to l
B.greater than l
C.less than l
D.depends on temperature change

Grade:11

1 Answers

Sandesh
34 Points
4 years ago
Lets assume inital length to be L, then resistor’s resistance r1 divided by semi conductor’s resistance r2 is L/(100-L). 
Now on heating r1 increases since collisions between the electrons and lattice increases. While on heating r2 decreases because no of free electrons inceases (that is  electrons move from valance band to conduction band). 
Therefore newr1/newr2 increases, hence new L will be grater than L.

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