Question

The dependence of resistance (R) of a conducting wire on its length (l) is given by:
1. \(R \propto \frac{1}{l}\)
2. \(R \propto l\)
3. \(R \propto \frac{1}{l^2}\)
4. \(R \propto l^2\)
5. Does not depend on length

Answer 1

Correct Answer - Option 2 : \(R \propto l\)

The correct answer is \(R \propto l\) .

 

• The resistance R of a cylinder of length L and cross-sectional area A is given by the formula:

\(R= ρL/A\)

Thus the resistance of the body is directly proportional to the length and resistivity of material & inversely proportional to its cross-sectional area.

 

• Ohms Law
  • Ohms Law says that when a voltage (V) is applied between two points in a circuit, an electrical current (I) starts to flow between them supported by the presence of the potential difference between these two points.
  • The amount of electrical current which flows is regulated by the amount of resistance (R) present.
  • In other words, the voltage encourages the current to flow (the flow of charge), but it is resistance that discourages it.