Assertion : A wire of uniform cross-section and uniform resistivity is connected across an ideal cell. Now the length or wire is doubled keeping volume of wire constant. The drift velocity of electrons after stretching the wire becomes one fourth of what it was before streching the wire.
Reason: If a wire (or uniform resistivity and uniform cross-section) of length `l_(0)` is stretched by a factor n, then its resistance becomes `n^(2)` times the one before stretching the wire (the volume of wire is kept constant in stretching process.) Fruther at constant potential difference, current is inversely proportional to resistance. Drift velocity of free electron is directly proportional to current and inversely proportional to cross-sectional area of current carrying wire.

Statement I: A wire of uniform cross-section and uniform resistivity is connected across an ideal cell. Now the length of the wire is doubled keeping volume of the wire constant. The drift velocity of electrons after stretching the wire becomes one-fouth of what it was before stretching the wire. Statement II: If a wire (of uniform resistivity and uniform cross section) of length l_0 is stretched to length nl_0 , then its resistance becomes n^2 times of what it was before stretching the wire (the volume of wire is kept constant in stretching process). Further at constant potential difference, current is inversely proportional to resistance. Finally, drift velocity of free electron is directly proportional to current and inversely proportional to cross-sectional area of current carrying wire.

A wire of non-uniform cross-section is carrying a steady current. Along the wire

A wire of non-uniform cross-section is carrying a steady current. Along the wire

The resistance of wire of length l and area of cross-section a is x ohm. If the wire is stretched to double its length, its resistance would become:

A wire with 15 Q resistance is stretched by one tenth of its original length and volume of wire is kept constant. Then its resistance will be