Question

What is electrical resistivity of a material? What is its unit? Describe an experiment to study the factors on which the resistance of conducting wire depends.

NCERT Class X
Science - Exemplar Problems

Chapter_Electricity

Answer 1

Resistivity is the property of the material that resists the flow of electrons through it. SI unit of resistivity is ohm (Ω).
The experiment involves setting up an circuit that consists of a battery resistance an rheostat an voltmeter and ammeter. On variable resistance the reading of voltmeter and ammeter should remain constant that is equal to Resistance. 
R = V/I which remains constant
Hence resistance depends on area and length of the conductor 

Answer 2

Answer:

hey dude your answer is below

Explanation:

Ans. The inherent property of a conductor because of which it resists the flow of electric

current is called resistivity. Resistivity for a particular material is unique,

(Ohm metre),

The SI unit of resistivity is Experiment to study the factors on which resistance of conducting wire depends:

• Take an ammeter, electric cell, plug key, nichrome wire and wires of different

materials

Make the circuit as shown in figure.

• Start the experiment with nichrome wire. Attach it in the circuit and take ammeter

reading

• Change the length of nichrome wire and take ammeter reading

• Change the thickness of nichrome wire and take ammeter reading

After above steps, use copper wire for the experiment. Attach a copper wire in the

circuit and take ammeter reading.

Change the length of copper wire and take ammeter reading,

Change the thickness of copper wire and take ammeter reading

• Repeat above steps with wires of different materials

Observations:

• It is seen that resistance depends on material of conductor.

Resistance depends on length of conductor.

• • Resistance depends on area of cross-section.