Electrostatics Question 642
Question: A sheet of aluminium foil of negligible thickness is introduced between the plates of a capacitor. The capacitance of the capacitor
Options:
A) Decreases
B) Remains unchanged
C) Becomes infinite
D) Increases
Show Answer
Answer:
Correct Answer: B
Solution:
[b] The capacitance of the capacitor with air as dielectric is given by $ C=\frac{{\varepsilon _{0}}A}{d}, $ Where A is the area of each plate and d is the distance between them.
The capacitance of the capacitor with a conducting shell of thickness t is given by $ C=\frac{{\varepsilon _{0}}A}{d-t}, $
Now, if $ t\to 0 $ , then $ C={\varepsilon _{0}}A/d $
Therefore, when a sheet of aluminium foil of negligible thickness is introduced between the plates of the capacitor, its capacitance remains unchanged.
