The resistance \(R\) of a uniform metallic conductor is directly proportional to its length (\(L\)) and inversely proportional to its cross-sectional area (\(A\)). This relationship is described by the following equation:
\(R = \rho \frac{L}{A}\)
where \(\rho\) (rho) is the resistivity of the material. Resistivity is a material property that reflects how strongly a material opposes the flow of electric current. Different materials have different resistivities. Therefore, the resistance of a conductor depends on:
- Length (\(L\)): A longer conductor has higher resistance because the electrons have to travel a greater distance.
- Area of cross-section (\(A\)): A larger cross-sectional area means there are more pathways for electrons to flow, thus reducing resistance.
- Nature of the material (\(\rho\)): The material's resistivity determines how easily electrons can move through it. A material with high resistivity will have a higher resistance.
Option 1, 2, and 3 are incorrect because they only consider one factor. Option 4 correctly identifies all three factors that influence the resistance of a uniform metallic conductor.
Similar Questions
If the length of a resistor is doubled, what happens to its resistance, assuming all other factors remain constant?
- The resistance of a particular material wire with length L and cross-sectional area A is 2 Ω. What would be the resistance of another wire of the same material having length 2L and area of cross-section A/2?
- Which of the following factors affect(s) the resistance of a wire?
- Which of the following statements is correct?
A cylindrical wire of length L and radius r has resistance R. The resistance of another wire of the same material but of twice its length and one-fourth its radius is:
- A cylindrical wire of length L and radius r has a resistance R. The resistance of another wire of the same material but half its length and half its radius will be:
- The length and the cross-sectional area of a conductor in the shape of a cylinder are '\(l\)' and '\(A\)' respectively. The resistivity of the material of the conductor is '\(\rho\)'. Its resistance depends upon
(p) \(l\) only
(q) \(l\) and \(A\)
(r) \(\rho\), \(l\) and \(A\)
(s) \(\rho\) and \(l\), but not \(A\)
Pick up the right option from those given above. - Resistivity of the wire depends on mainly ________
- The resistance of a metallic wire of length 1m and area of cross-section 1sq.metre having a resistivity is $2 \times 10^{-6}$ ohm - m is:
- A cylindrical wire of length \(L\) and radius \(r\) has a resistance \(R\). The resistance of another wire of same material but having four times its length and half its radius will be:
Important Questions from Resistance and Resistivity
Which of the following metals has the lowest electrical resistivity?
When electric current is passed through a wire, the amount of heat produced in a wire depends upon _______.
I. Length
II. Thickness
A uniform wire of resistance 9Ω is bent in the form of an equilateral triangle. Find the effective resistance across a side of the triangle.
The value of carbon resistance is 54 × 103 Ω. The percentage tolerance is 5%. What is the colour code sequence of carbon resistance?
Which of the following relations are wrong?
I. The specific conductance is given by the relation \(k = \frac{1}{R}\left( {l/A} \right)\)
II. The equivalent conducting is given by the relation \(\lambda = \frac{{100\;K}}{C}\)
III. The specific resistance is given by the relation \(\rho = \frac{{Rl}}{A}\)
