Q1. What is electrical resistivity? In a series electrical circuit comprising a resistor made up of a metallic wire, the ammeter reads 5 A. The reading if the ammeter decreases to half when the length of the wire is doubled. Why?

Q2. Should the resistance of an ammeter be low or high? Give reason.

Pleeeeeez answer and help with the above questions. The answers should be as per class 10 level. Pleeeeeeeeeeeeeeez help, would be appreciated!

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Answers

The Brainliest Answer!
2015-06-16T20:08:02+05:30
A1. Electrical resistivity is defined a the resistance of a conductor of length 1m and area of cross section 1m sq.. When the length of the wire is doubled, its resistance also doubles (increases), a resistance is directly proportional to length of the wire.
R α l
When its resistance increases, its current decreases, as resistance is inversely proportional to current. 
R α 1/I

A2.  An ammeter measures electric current. It should have a very low resistance, so that it doesn't change the value of current flowing through the circuit.

*By the way, even I'm a class 10th student.
2 5 2
Thanxx sosososo much for helping! Means a ton! :)
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