A bag contains a mixture of two solids A and B, solid A being lighter than solid B. Solid A is an impurity which needs to be removed. What type of separating method will you use to obtain pure solid B?

Options

A. Sieving
B. Threshing
C. Winnowing
D. Magnetic separation

Answer

To separate the mixture of solids A and B, where solid A is lighter and an impurity, we can use the following method:

### Step-by-Step Solution:

1. **Identify the Properties of the Mixture**:
- Solid A is lighter than solid B.
- Solid A is the impurity that needs to be removed.

2. **Choose the Appropriate Separation Method**:
- Since solid A is lighter, we can utilize a method that takes advantage of the difference in weight between the two solids.

3. **Use the Winnowing Technique**:
- Winnowing is a method commonly used to separate lighter components from heavier ones using wind or air.
- In this case, we will blow air over the mixture.

4. **Perform the Separation**:
- When air is blown over the mixture, the lighter solid A will be carried away by the wind, while the heavier solid B will remain behind.

5. **Collect the Separated Solids**:
- After the winnowing process, collect solid B, which is now pure and free from the lighter impurity solid A.

### Final Answer:
The suitable method to obtain pure solid B from the mixture is **winnowing**.

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