Question

1) a) Define resistance of a condutor ?
b) State the factors on which resistance of a conductor depends?
c) name the device which is often used to change the resistance without changing the voltage source in an electric circuit?​

Answer 1

Explanation:

a. Resistance is defined as the opposition to the flow of electrical current through a conductor. ... It's important to point out that conductivity and resistivity (the property that determines final resistance) are inversely proportional.

b. resistivity

The resistance of a conductor depends on the cross sectional area of the conductor, the length of the conductor, and its resistivity.

c. Potentiometer

Potentiometer are used often to change the resistance without changing the voltage source in an electric circuit.

Answer 2

Resistance is defined as the property of a conductor to resist the flow of charges through it.

• It is equal to the ratio of potential difference across a conductor and the current passing through that conductor.
• R=V/I.
• where, V-potential difference and I-current.
• Its S.I. unit is ohm(Ω).
• It does not depend upon the potential difference and the current.
• It depends on the material of the conductor, its characteristics like its length, its area and its resistivity.
• R=ρ(l/A)
• where, ρ-resistivity, l-length and A-area.
• It also varies with the temperature.
• Rheostat is used to change the resistance without changing the voltage source in an electric circuit.

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