Choose the correct option for each question. There is only one correct response for each question.
Which of these will generate the maximum amount of heat when rubbed against each other?

Options

A. Two plane polished surfaces of wood
B. Two plane unpolished surfaces of wood
C. Two plane polished oil-coated surfaces of wood.
D. One plane polished surface of the wood with another surface coated with oil

Answer

To determine which option generates the maximum amount of heat when rubbed against each other, we need to analyze the friction produced by the surfaces in contact. Here’s the step-by-step solution:

### Step 1: Understand the relationship between friction and heat
- Friction is the force that opposes the relative motion of two surfaces in contact. When two surfaces rub against each other, friction generates heat.
- The amount of heat produced is directly proportional to the amount of friction; more friction means more heat.

### Step 2: Identify the roughness of the surfaces
- The roughness of the surfaces plays a crucial role in determining the amount of friction. Rough surfaces create more friction compared to smooth surfaces.
- Therefore, to maximize heat generation, we need to find the option with the roughest surfaces.

### Step 3: Analyze the options
1. **Two plain polished surfaces of wood**: Polished surfaces are smooth, leading to low friction and low heat.
2. **Two plain unpolished surfaces of wood**: Unpolished surfaces are rougher than polished ones, resulting in higher friction and more heat than the first option.
3. **Two plain polished oil-coated surfaces**: Both polished and oil-coated surfaces are smooth, resulting in very low friction and minimal heat generation.
4. **One polished surface of wood and one surface coated with oil**: One surface is smooth (polished) and the other is smooth (oil-coated), leading to low friction and low heat.

### Step 4: Determine which option produces the most heat
- Among the options, the second option (two plain unpolished surfaces of wood) has the roughest surfaces, which means it will generate the most friction and therefore the most heat.

### Conclusion
- The correct option that generates the maximum amount of heat when rubbed against each other is **Option B: Two plain unpolished surfaces of wood**.

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