Two parallel metal plates having charges `+Q` and `-Q` face each other at a certain distance between them.If the plates are now dipped in kerosene oil tank ,the electric field between the plates will

Options

A. becomes zero
B. increase
C. decrease
D. remain same

Explanation

To solve the problem, we need to analyze how the electric field between two parallel plates changes when they are immersed in a dielectric medium, such as kerosene oil.

### Step-by-Step Solution:

1. **Understanding the Electric Field Between Plates**:
The electric field (E) between two parallel plates with charges +Q and -Q in a vacuum is given by the formula:
\[ E = \frac{\sigma}{\epsilon_0} \]
where \(\sigma\) is the surface charge density and \(\epsilon_0\) is the permittivity of free space.

2. **Effect of Immersing in a Dielectric**:
When the plates are immersed in a dielectric medium (like kerosene oil), the electric field is modified by the dielectric constant (k) of the medium. The new electric field (E') in the dielectric can be expressed as:
\[ E' = \frac{E}{k} \]
where \(k\) is the dielectric constant of the medium.

3. **Conclusion on the Electric Field**:
Since \(k > 1\) for any dielectric medium, it follows that:
\[ E' < E \]
This means that the electric field between the plates decreases when they are dipped in kerosene oil.

### Final Answer:
The electric field between the plates will **decrease** when they are dipped in kerosene oil.

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