Which among the following is not a part of electroscope?

Options

A. metal disc
B. metal rod
C. metal strip
D. metal plate

Explanation

To determine which option is not a part of an electroscope, we can follow these steps:

### Step 1: Understand what an electroscope is
An electroscope is a device used to detect electric charge. It can indicate whether an object is charged and the nature of the charge (positive or negative).

### Step 2: Identify the parts of an electroscope
There are two main types of electroscopes:
1. **Pith Ball Electroscope**
2. **Gold Leaf Electroscope**

The Gold Leaf Electroscope typically consists of:
- A **metal disc** at the top
- A **metal rod** that connects the disc to the leaves
- **Metal strips** (gold leaves) that diverge when charged

### Step 3: Analyze the options given
The options provided are:
1. Metal disc
2. Metal rod
3. Metal strips
4. Metal plate

### Step 4: Determine which option is not part of an electroscope
From our analysis:
- The **metal disc**, **metal rod**, and **metal strips** are all parts of the Gold Leaf Electroscope.
- The **metal plate** is not a standard component of either type of electroscope.

### Conclusion
Thus, the option that is not a part of an electroscope is **metal plate**.

### Final Answer
**Metal plate** is not a part of an electroscope.

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