Question

On which factors and how do the following depend? 

(i) Internal resistance of cell 
(ii) Resistance of conductor

Hint:

To reduce conductor resistance, choose materials with low resistivity and increase the cross-sectional area.

Answer 1

i. Internal resistance of cell Step 1: The internal resistance of a cell depends on several factors: \[ r \propto \frac{\text{distance between electrodes}}{\text{area of electrodes}} \] - It increases if the distance between electrodes increases. 
- It decreases if the cross-sectional area of electrodes increases. 
- It depends on the electrolyte's concentration and nature. \[ \text{Thus, the internal resistance can be minimized by using a highly conductive electrolyte and optimizing electrode placement.} \] \[ \boxed{\text{Factors: Distance, area, electrolyte nature, and temperature}} \] 

ii. Resistance of conductor 

Step 1: The resistance of a conductor is given by: \[ R = \rho \frac{L}{A} \] where: - \( R \) is resistance,
- \( \rho \) is resistivity, 
- \( L \) is length, 
- \( A \) is cross-sectional area. 

Step 2: Factors affecting resistance: - It increases with an increase in length (\( L \)). 
- It decreases with an increase in cross-sectional area (\( A \)). 
- Different materials have different resistivities. 
- Resistance increases with temperature due to an increase in resistivity. \[ \text{Therefore, resistance can be controlled by choosing appropriate materials and dimensions.} \] \[ \boxed{\text{Factors: Length, cross-sectional area, material, and temperature}} \]