Rankers Physics

Capacitors: Practice Problem & Solution

The electrostatic force between the metal plates of an isolated parallel plate capacitor $C$ having a charge $Q$ and area $A$, is (2018)
Proportional to the square root of the distance between the plates.
Linearly proportional to the distance between the plates.
Independent of the distance between the plates.
Inversely proportional to the distance between the plates.

Short Solution (Best for NEET):

To solve this problem, we apply the core principles of Capacitors. Understanding the underlying formula is key to arriving at the correct answer below:

The electrostatic force between the plates of a parallel plate capacitor is given by $F = \frac{Q^2}{2A\varepsilon_0}$. This formula shows that the force depends on charge and area but is completely independent of the distance between the plates.

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Similar Practice Questions

Explore conceptually related problems to test your knowledge.

1. In a charged capacitor, the energy resides in
2. Two identical charged spheres are suspended by strings of equal lengths. The strings make an angle of 30° with each other. When suspended in a liquid of density \(0.8\text{ g cm}^{-3}\), the angle remains the same. If density of the material of the sphere is \(1.6\text{ g cm}^{-3}\), the dielectric constant of the liquid is :
3. It is required to construct a \(10\text{ \mu F}\) capacitor which can be connected across a \(200\text{ V}\) battery. Capacitors of capacitance \(10\text{ \mu F}\) are available but they can withstand only \(50\text{ V}\). Design a combination which can yield the desired result.
4. A \(5.0~\mu\text{F}\) capacitor having a charge of \(20~\mu\text{C}\) is discharged through a wire of resistance \(5.0~\Omega\). Find the heat dissipated in the wire between 25 to 50 \(\mu\text{s}\) after the connections are made.
5. Assertion (A): If separation between plates of a parallel plate isolated charged capacitor is increased, its energy stored will be increased. Reason (R): Work done to separate the plates get converted in electrostatic potential energy.