Question

A wire of resistivity p is stretched to three times its length. What will be its new resistivity 2
Tap water conducts electricity whereas distilled water does not. Why?
Define resistivity of a material​

Answer 1

#1 Answer: When wire is stretched 3 times of its original strength, it’s resistance will increase 9 times, because when length increase radius decrease i.e. area decreases.

#2 Answer: Tao water contains dissolved salts in it. These salts dissociates into ions when electricity passed through it which are responsible for the electricity conductivity of tap water. But, distilled water does not contain any dissolved salts, so it does not conduct electricity,

#3 Answer: The resistivity of a material is the resistance of a wire of that material of unit length and unit cross-sectional area. The unit of resistivity is the ohm-meter. The resistivity of a material depends on its nature and the temperature of the conductor, but not it’s shape and size.