From the following, what charges can be present on oil drops in Millikan's experiment ?

Options

A. Zero, equal to the magnitude of charge on `alpha`-particle
B. `Ze, 1.6 xx 10^(-18)C`
C. `1.6 xx 10^(-19) C, 2.5 e`
D. `1.5 e, e`

Explanation

To determine the possible charges on oil drops in Millikan's experiment, we need to understand the fundamental principles behind the experiment and the nature of the charges involved.

### Step-by-Step Solution:

1. **Understanding Millikan's Experiment**:
- Millikan's oil drop experiment was designed to measure the charge of the electron. In this experiment, tiny oil droplets are charged and then suspended in an electric field.

2. **Charge Quantization**:
- The key finding from Millikan's experiment is that the charges on the oil drops are quantized. This means that the charges can only take on certain discrete values, which are integral multiples of the elementary charge (e).

3. **Elementary Charge (e)**:
- The elementary charge (e) is approximately \(1.6 \times 10^{-19}\) coulombs. Thus, the possible charges on the oil drops can be expressed as \(n \cdot e\), where \(n\) is an integer (0, 1, 2, 3, ...).

4. **Evaluating the Options**:
- **Option A: 0** - This is incorrect because while it is theoretically possible for a drop to have no charge, the experiment specifically measures charged drops.
- **Option B: 2E** - This is valid since it represents \(2 \cdot e\), which is a multiple of the elementary charge.
- **Option C: \(1.6 \times 10^{-18}\) coulombs** - This is also valid as it equals \(10 \cdot e\) (since \(10 \cdot 1.6 \times 10^{-19} = 1.6 \times 10^{-18}\)).
- **Option D: \(1.6 \times 10^{-19}\) coulombs** - This is valid as it equals \(1 \cdot e\).
- **Option E: \(1.6 \times 10^{8}\) coulombs** - This is incorrect as it is not a multiple of the elementary charge and is an excessively large value.

5. **Conclusion**:
- The charges that can be present on oil drops in Millikan's experiment are integral multiples of the elementary charge. Therefore, valid options include \(2E\), \(1.6 \times 10^{-18}\) coulombs, and \(1.6 \times 10^{-19}\) coulombs.

### Final Answer:
The possible charges on oil drops in Millikan's experiment can be \(2E\), \(1.6 \times 10^{-18}\) coulombs, and \(1.6 \times 10^{-19}\) coulombs.